A Decision Making PowerPoint Slides by Copyright Jeff Heyl © 2010 Pearson Education, Inc. Publishing as Prentice Hall. For Operations Management, 9e by Krajewski/Ritzman/Malhotra © 2010 Pearson Education A–1 Break-Even.
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Slide 1
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 2
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 3
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 4
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 5
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 6
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 7
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
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A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 8
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 9
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
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A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
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A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 10
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
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A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
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A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
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A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
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A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 11
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 12
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 13
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 14
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 15
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 16
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 17
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 18
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 19
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 20
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 21
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 22
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 23
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 24
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 25
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 26
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
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A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
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A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
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A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
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A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
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A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
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A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
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A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
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A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
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A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
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A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
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A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
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A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
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A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
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A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
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A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
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A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
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A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
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A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
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A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
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A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 27
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 28
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 29
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 30
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 31
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 32
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
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A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 33
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
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A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
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A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
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A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
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A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
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A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
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A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 34
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
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A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 35
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 36
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 37
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 38
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 39
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 40
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 41
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 42
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 43
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 44
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 45
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 46
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
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A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 47
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 48
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
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A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
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A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
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A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
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A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
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A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 49
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
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A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
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A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
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A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
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A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
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A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 50
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 51
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
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A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
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A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
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A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
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A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
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A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
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A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
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A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
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A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
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A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
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A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 52
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 53
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 54
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 55
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 56
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
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A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 57
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
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A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
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A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
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A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 58
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
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A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
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A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 59
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 60
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 61
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
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A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 62
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 63
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 64
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 65
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
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A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
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A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
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A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
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A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 66
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 67
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 68
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 2
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 3
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
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A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
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A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
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A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
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A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
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A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 4
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 5
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 6
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 7
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 8
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
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A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 9
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 10
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 11
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 12
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 13
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 14
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
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A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 15
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 16
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 17
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 18
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 19
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 20
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 21
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 22
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
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A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
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A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
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A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
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A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
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A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
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A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
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A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
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A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
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A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
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A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
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A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
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A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
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A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
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A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
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A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
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A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
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A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
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A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
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A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
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A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
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A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
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A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
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A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
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A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
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A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
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A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 23
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 24
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 25
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 26
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 27
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 28
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 29
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
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A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
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A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
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A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
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A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 30
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
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A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 31
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
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A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 32
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 33
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 34
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 35
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 36
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
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A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 37
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 38
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 39
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 40
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 41
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 42
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
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A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
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A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 43
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 44
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
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A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
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A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
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A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
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A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
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A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 45
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
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A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
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A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
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A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
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A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 46
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 47
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
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A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
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A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
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A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
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A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
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A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
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A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
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A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
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A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
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A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
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A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
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A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 48
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 49
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 50
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 51
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 52
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
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A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 53
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
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A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
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A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
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A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
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A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
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A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 54
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 55
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 56
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
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A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 57
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
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A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 58
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 59
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 60
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 61
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
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A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
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A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
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A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
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A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
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A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
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A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 62
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
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A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 63
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 64
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 65
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 66
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 68
Slide 67
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
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A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
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A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
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A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
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A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
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A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
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A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
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A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
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A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
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A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
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A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
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A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
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A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
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A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
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A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
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A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
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A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
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A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
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A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
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A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
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A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 67
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A – 68
Slide 68
A
Decision Making
PowerPoint Slides
by Copyright
Jeff Heyl
© 2010 Pearson Education, Inc. Publishing as Prentice Hall.
For Operations Management, 9e by
Krajewski/Ritzman/Malhotra
© 2010 Pearson Education
A–1
Break-Even Analysis
Evaluating Services or Products
Is
the predicted sales volume of the service or
product sufficient to break even (neither
earning a profit nor sustaining a loss)?
How
low must the variable cost per unit be to
break even, based on current prices and sales
forecasts?
How
low must the fixed cost be to break even?
How
do price levels affect the break-even
quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–2
Break-Even Analysis
Break-even analysis is based on the assumption
that all costs related to the production of a specific
service or product can be divided into two
categories: variable costs and fixed costs
Variable cost, c, is the portion of the total cost that
varies directly with volume of output
If Q = the number of customers served or units
produced per year, total variable cost = cQ
Fixed cost, F, is the portion of the total cost that
remains constant regardless of changes in levels
of output
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–3
Break-Even Analysis
So
Total cost = F + cQ
Total revenue = pQ
By setting revenue equal to total cost
pQ = F + cQ
F
Q=
p-c
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–4
Finding the Break-Even Quantity
EXAMPLE A.1
A hospital is considering a new procedure to be offered at $200
per patient. The fixed cost per year would be $100,000, with
total variable costs of $100 per patient. What is the break-even
quantity for this service? Use both algebraic and graphic
approaches to get the answer.
SOLUTION
The formula for the break-even quantity yields
100,000
F
=
Q=
= 1,000 patients
p-c
200 – 100
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–5
Finding the Break-Even Quantity
To solve graphically we plot two lines: one for costs and one
for revenues
Begin by calculating costs and revenues for two different
output levels
The following table shows the results for Q = 0 and Q = 2,000
Quantity
(patients) (Q)
Total Annual Cost ($)
(100,000 + 100Q)
Total Annual Revenue ($)
(200Q)
0
100,000
0
2,000
300,000
400,000
Draw the cost line through points (0, 100,000) and (2,000,
300,000)
Draw the revenue line through (0, 0) and (2,000, 400,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–6
Finding the Break-Even Quantity
Dollars (in thousands)
400 –
300 –
(2000, 400)
Profits
Total annual revenues
(2000, 300)
Total annual costs
200 –
Break-even quantity
100 –
Loss
0–
Fixed costs
|
|
|
|
500
1000
1500
2000
The two lines
intersect at
1,000 patients,
the break-even
quantity
Patients (Q)
FIGURE A.1 – Graphic Approach to Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–7
Application A.1
The Denver Zoo must decide whether to move twin polar bears
to Sea World or build a special exhibit for them and the zoo.
The expected increase in attendance is 200,000 patrons. The
data are:
Revenues per Patron for Exhibit
Gate receipts
$4
Concessions
$5
Licensed apparel
$15
Estimated Fixed Costs
Exhibit construction
Salaries
Food
$2,400,000
$220,000
$30,000
Is the
predicted
increase in
attendance
sufficient to
break even?
Estimated Variable Costs per Person
Concessions
$2
Licensed apparel
$9
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–8
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
7–
Cost and revenue
(millions of dollars)
6–
5–
4–
3–
2–
1–
|
0–
|
|
|
|
|
50
100
150
200
250
Q (thousands of patrons)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A–9
Application A.1
Q
0
250,000
TR = pQ
$0
$6,000,000
TC = F + cQ
$2,650,000
$5,400,000
Where
p = 4 + 5 + 15 = $24
F = 2,400,000 + 220,000 + 30,000
= $2,650,000
c = 2 + 9 = $11
Algebraic solution of Denver Zoo problem
pQ = F + cQ
24Q = 2,650,000 + 11Q
13Q = 2,650,000
Q = 203,846
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 10
Sensitivity Analysis
EXAMPLE A.2
If the most pessimistic sales forecast for the proposed service
in Figure A.1 were 1,500 patients, what would be the
procedure’s total contribution to profit and overhead per year?
SOLUTION
The graph shows that even the pessimistic forecast lies above
the break-even volume, which is encouraging. The product’s
total contribution, found by subtracting total costs from total
revenues, is
pQ – (F + cQ) = 200(1,500) – [100,000 + 100(1,500)]
= $50,000
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A – 11
Evaluating Processes
Choices must be made between two
processes or between an internal process
and buying services or materials on the
outside
We assume that the decision does not
affect revenues
The analyst finds the quantity for which the
total costs for two alternatives are equal
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 12
Evaluating Processes
Let Fb equal the fixed cost (per year) of the buy
option, Fm equal the fixed cost of the make option,
cb equal the variable cost (per unit) of the buy
option, and cm equal the variable cost of the make
option
The total cost to buy is Fb + cbQ and the total cost
to make is Fm + cmQ
To find the break-even quantity, we set the two
cost functions equal and solve for Q:
Fb + cbQ = Fm + cmQ
Fm – Fb
Q= c –c
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 13
Break-Even Analysis for
Make-or-Buy Decisions
EXAMPLE A.3
A fast-food restaurant featuring hamburgers is adding salads
to the menu
The price to the customer will be the same
Fixed costs are estimated at $12,000 and variable costs
totaling $1.50 per salad
Preassembled salads could be purchased from a local
supplier at $2.00 per salad
Preassembled salads would require additional refrigeration
with an annual fixed cost of $2,400
Expected demand is 25,000 salads per year
What is the break-even quantity?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 14
Break-Even Analysis for
Make-or-Buy Decisions
SOLUTION
The formula for the break-even quantity yields the following:
Fm – Fb
Q= c –c
b
m
=
12,000 – 2,400
= 19,200 salads
2.0 – 1.5
Figure A.2 shows the solution from OM Explorer’s BreakEven Analysis Solver. The break-even quantity is 19,200
salads. As the 25,000-salad sales forecast exceeds this
amount, the make option is preferred. Only if the restaurant
expected to sell fewer than 19,200 salads would the buy
option be better.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 15
Break-Even Analysis for
Make-or-Buy Decisions
FIGURE A.2 – Break-Even Analysis
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
Solver of OM Explorer for Example A.3
A – 16
Application A.2
At what volume should the Denver Zoo be indifferent
between buying special sweatshirts from a supplier or have
zoo employees make them?
Buy
Make
Fixed costs
$0
$300,000
Variable costs
$9
$7
$300,000 – $0
Fm – Fb
Q= c –c =
= $150,000
$9
–
$7
b
m
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 17
Preference Matrix
A Preference Matrix is a table that allows you to
rate an alternative according to several
performance criteria
The criteria can be scored on any scale as long as
the same scale is applied to all the alternatives
being compared
Each score is weighted according to its perceived
importance, with the total weights typically
equaling 100
The total score is the sum of the weighted scores
(weight × score) for all the criteria and compared
against scores for alternatives
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A – 18
Evaluating an Alternative
EXAMPLE A.4
The following table shows the performance criteria, weights,
and scores (1 = worst, 10 = best) for a new thermal storage air
conditioner. If management wants to introduce just one new
product and the highest total score of any of the other product
ideas is 800, should the firm pursue making the air conditioner?
Performance Criterion
Weighted Score (A B)
Weight (A)
Score (B)
Market potential
30
8
240
Unit profit margin
20
10
200
Operations compatibility
20
6
120
Competitive advantage
15
10
150
Investment requirements
10
2
20
5
4
20
Project risk
Weighted score =
750
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 19
Evaluating an Alternative
SOLUTION
Because the sum of the weighted scores is 750, it falls short of
the score of 800 for another product. This result is confirmed by
the output from OM Explorer’s Preference Matrix Solver in
Figure A.3.
Total
750
FIGURE A.3 – Preference Matrix Solver for Example A.4
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 20
Application A.3
Performance Criterion
Weight
Score
Market potential
10
5
Unit profit margin
30
8
Operations compatibility
20
10
Competitive advantage
25
7
Investment requirements
10
3
5
4
Project risk
Weighted Score
Total weighted score =
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 21
Application A.3
Performance Criterion
Weight
Score
Weighted Score
Market potential
10
5
50
Unit profit margin
30
8
240
Operations compatibility
20
10
200
Competitive advantage
25
7
175
Investment requirements
10
3
30
5
4
20
Project risk
Total weighted score = 715
Repeat this process for each alternative – pick the one
with the largest weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 22
Criticisms
Requires the manager to state criterion
weights before examining alternatives, but
they may not know in advance what is
important and what is not
Allows one very low score to be overridden
by high scores on other factors
May cause managers to ignore important
signals
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 23
Decision Theory
Decision theory is a general approach to decision
making when the outcomes associated with
alternatives are in doubt
A manager makes choices using the following
process:
1. List a reasonable number of feasible alternatives
2. List the events (states of nature)
3. Calculate the payoff table showing the payoff for each
alternative in each event
4. Estimate the probability of occurrence for each event
5. Select the decision rule to evaluate the alternatives
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 24
Decision Making Under Certainty
The simplest solution is when the
manager knows which event will occur
Here the decision rule is to pick the
alternative with the best payoff for the
known event
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 25
Decisions Under Certainty
EXAMPLE A.5
A manager is deciding whether to build a small or a large
facility
Much depends on the future demand
Demand may be small or large
Payoffs for each alternative are known with certainty
What is the best choice if future demand will be low?
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 26
Decisions Under Certainty
SOLUTION
The best choice is the one with the highest payoff
For low future demand, the company should build a small
facility and enjoy a payoff of $200,000
Under these conditions, the larger facility has a payoff of
only $160,000
Possible Future Demand
Alternative
Low
High
Small facility
200
270
Large facility
160
800
0
0
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 27
Decision Making Under Uncertainty
Can list the possible events but can not
estimate the probabilities
1. Maximin: The best of the worst, a pessimistic
approach
2. Maximax: The best of the best, an optimistic
approach
3. Laplace: The alternative with the best weighted
payoff assuming equal probabilities
4. Minimax Regret: Minimizing your regret (also
pessimistic)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 28
Decisions Under Uncertainty
EXAMPLE A.6
Reconsider the payoff matrix in Example A.5. What is the best
alternative for each decision rule?
SOLUTION
a. Maximin. An alternative’s worst payoff is the lowest number
in its row of the payoff matrix, because the payoffs are
profits. The worst payoffs ($000) are
Alternative
Worst Payoff
Small facility
200
Large facility
160
The best of these worst numbers is $200,000, so the
pessimist would build a small facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 29
Decisions Under Uncertainty
b. Maximax. An alternative’s best payoff ($000) is the highest
number in its row of the payoff matrix, or
Alternative
Best Payoff
Small facility
270
Large facility
800
The best of these best numbers is $800,000, so the optimist
would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 30
Decisions Under Uncertainty
c. Laplace. With two events, we assign each a probability of
0.5. Thus, the weighted payoffs ($000) are
Alternative
Weighted Payoff
Small facility
0.5(200) + 0.5(270) = 235
Large facility
0.5(160) + 0.5(800) = 480
The best of these weighted payoffs is $480,000, so the
realist would build a large facility
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 31
Decisions Under Uncertainty
d. Minimax Regret. If demand turns out to be low, the best
alternative is a small facility and its regret is 0 (or 200 –
200). If a large facility is built when demand turns out to be
low, the regret is 40 (or 200 – 160).
Regret
Alternative
Low Demand
High Demand
Maximum
Regret
Small facility
200 – 200 = 0
800 – 270 = 530
530
Large facility
200 – 160 = 40
800 – 800 = 0
40
The column on the right shows the worst regret for each
alternative. To minimize the maximum regret, pick a large
facility. The biggest regret is associated with having only a
small facility and high demand.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 32
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 33
Application A.4
Fletcher (a realist), Cooper (a pessimist), and Wainwright (an
optimist) are joint owners in a company. They must decide
whether to make Arrows, Barrels, or Wagons. The government
is about to issue a policy and recommendation on pioneer
travel that depends on whether certain treaties are obtained.
The policy is expected to affect demand for the products;
however it is impossible at this time to assess the probability of
these policy “events.” The following data are available:
Payoffs (Profits)
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 34
Application A.4
Which product would be favored by Fletcher (realist)?
Which product would be favored by Cooper (pessimist)?
Which product would be favored by Wainwright (optimist)?
What is the minimax regret solution?
Payoffs (Profits)
Alternative
The short answers
are:
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Fletcher (realist – Laplace) would choose arrows
Cooper (pessimist – Maximin) would choose barrels
Wainwright (optimist – Maximax) would choose wagons
The Minimax Regret solution is arrows
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 35
Decisions Under Risk
The manager can list the possible events
and estimate their probabilities
The manager has less information than
decision making under certainty, but more
information than with decision making
under uncertainty
The expected value rule is widely used
This rule is similar to the Laplace decision
rule, except that the events are no longer
assumed to be equally likely
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 36
Decisions Under Risk
EXAMPLE A.7
Reconsider the payoff matrix in Example A.5. For the expected
value decision rule, which is the best alternative if the
probability of small demand is estimated to be 0.4 and the
probability of large demand is estimated to be 0.6?
SOLUTION
The expected value for each
alternative is as follows:
Alternative
Possible Future
Demand
Alternative
Small
Large
Small facility
200
270
Large facility
160
800
Expected Value
Small facility
0.4(200) + 0.6(270) = 242
Large facility
0.4(160) + 0.6(800) = 544
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 37
Application A.5
For Fletcher, Cooper, and Wainwright, find the best decision
using the expected value rule. The probabilities for the events
are given below.
Payoffs (Profits)
What alternative has
the best expected
results?
Alternative
Land Routes
No treaty
Land Routes
Treaty
Sea Routes
Only
Arrows
$840,000
$440,000
$190,000
Barrels
$370,000
$220,000
$670,000
Wagons
$25,000
$1,150,000
($25,000)
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Arrows
(0.50)(840,000)
+
(0.30)(440,000) + (0.20)(190,000)
= 590,000
Barrels
(0.50)(370,000)
+
(0.30)(220,000) + (0.20)(670,000)
= 385,000
Wagons
(0.50)(25,000)
+
(0.30)(1,150,000) +
Sea routes,
Only (0.20)
(0.20)(-25,000)
Expected
Value
= 352,500
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 38
Decision Trees
Are schematic models of available
alternatives and possible consequences
Are useful with probabilistic events and
sequential decisions
Square nodes represent decisions
Circular nodes represent events
Events leaving a chance node are
collectively exhaustive
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 39
Decision Trees
Conditional payoffs for each possible
alternative-event combination shown at
the end of each combination
Draw the decision tree from left to right
Calculate expected payoff to solve the
decision tree from right to left
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 40
Decision Trees
E1 & Probability
E2 & Probability
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Alternative 3
1
1st
decision
2
Alternative 4
Alternative 5
Possible
2nd decision
E2 & Probability
= Event node
E3 & Probability
Payoff 1
Payoff 2
Payoff 3
Payoff 1
Payoff 2
= Decision node
Ei = Event i
P(Ei) = Probability of event i
FIGURE A.4 – A Decision Tree Model
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 41
Decision Trees
After drawing a decision tree, we solve it
by working from right to left, calculating
the expected payoff for each of its
possible paths
1. For an event node, we multiply the payoff of
each event branch by the event’s probability
and add these products to get the event
node’s expected payoff
2. For a decision node, we pick the alternative
that has the best expected payoff
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 42
Decision Trees
Various software is available for drawing
and/or analyzing decision trees, including
PowerPoint can be used to draw decision
trees, but does not have the capability to
analyze the decision tree
POM with Windows
SmartDraw
PrecisionTree decision analysis from Palisade
Corporation
TreePlan
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 43
Analyzing a Decision Tree
EXAMPLE A.8
A retailer will build a small or a large facility at a new location
Demand can be either small or large, with probabilities
estimated to be 0.4 and 0.6, respectively
For a small facility and high demand, not expanding will have
a payoff of $223,000 and a payoff of $270,000 with expansion
For a small facility and low demand the payoff is $200,000
For a large facility and low demand, doing nothing has a
payoff of $40,000
The response to advertising may be either modest or sizable,
with their probabilities estimated to be 0.3 and 0.7,
respectively
For a modest response the payoff is $20,000 and $220,000 if
the response is sizable
For a large facility and high demand the payoff is $800,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 44
Analyzing a Decision Tree
SOLUTION
The decision tree in Figure A.5 shows the event probability
and the payoff for each of the seven alternative-event
combinations. The first decision is whether to build a small or
a large facility. Its node is shown first, to the left, because it is
the decision the retailer must make now. The second decision
node is reached only if a small facility is built and demand
turns out to be high. Finally, the third decision point is
reached only if the retailer builds a large facility and demand
turns out to be low.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 45
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 46
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
0.3 x $20 = $6
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$6 + $154 = $160
Sizable response [0.7]
$220
0.7 x $220 = $154
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 47
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 48
Analyzing a Decision Tree
Low demand [0.4]
$200
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 49
Analyzing a Decision Tree
Low demand [0.4]
$200
x 0.4 = $80
$80 + $162 = $242
Don’t expand
$223
2
Expand
$270
1
$270
x 0.6 = $162
Do nothing
$40
3
Modest response [0.3]
$20
Advertise
$160
$160
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 50
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
3
$20
Advertise
$160
0.4 x $160 = $64
$544
Modest response [0.3]
$160
High demand [0.6]
$800
Sizable response [0.7]
$220
x 0.6 = $480
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 51
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 52
Analyzing a Decision Tree
Low demand [0.4]
$200
$242
Don’t expand
$223
2
Expand
$270
1
$270
Do nothing
$40
$544
3
$20
Advertise
$160
$160
$544
Modest response [0.3]
Sizable response [0.7]
$220
High demand [0.6]
$800
FIGURE A.5 – Decision Tree for Retailer (in $000)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 53
Application A.6
a. Draw the decision tree for the Fletcher, Cooper, and
Wainwright Application A.5 problem
b. What is the expected payoff for the best alternative in the
decision tree below?
Alternative
Land routes,
No Treaty
(0.50)
Land Routes,
Treaty Only
(0.30)
Sea routes,
Only (0.20)
Arrows
840,000
440,000
190,000
Barrels
370,000
220,000
670,000
Wagons
25,000
1,150,000
-25,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 54
Application A.6
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 55
Solved Problem 1
A small manufacturing business has patented a new device
for washing dishes and cleaning dirty kitchen sinks
The owner wants reasonable assurance of success
Variable costs are estimated at $7 per unit produced and
sold
Fixed costs are about $56,000 per year
a. If the selling price is set at $25, how many units must be
produced and sold to break even? Use both algebraic
and graphic approaches.
b. Forecasted sales for the first year are 10,000 units if the
price is reduced to $15. With this pricing strategy, what
would be the product’s total contribution to profits in the
first year?
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 56
Solved Problem 1
SOLUTION
a. Beginning with the algebraic approach, we get
56,000
F
=
Q=
p–c
25 – 7
= 3,111 units
Using the graphic approach, shown in Figure A.6, we first
draw two lines:
Total revenue = 25Q
Total cost = 56,000 + 7Q
The two lines intersect at Q = 3,111 units, the break-even
quantity
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 57
Solved Problem 1
b. Total profit contribution = Total revenue – Total cost
= pQ – (F + cQ)
= 15(10,000) – [56,000 + 7(10,000)]
= $24,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 58
Solved Problem 1
250 –
Dollars (in thousands)
200 –
Total revenues
150 –
Break-even
quantity
100 –
$77.7
Total costs
50 –
3.1
0–
FIGURE A.6
|
|
|
|
|
|
|
|
1
2
3
4
5
6
7
8
Units (in thousands)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 59
Solved Problem 2
Binford Tool Company is screening three new product idea: A,
B, and C. Resource constraints allow only one of them to be
commercialized. The performance criteria and ratings, on a
scale of 1 (worst) to 10 (best), are shown in the following table.
The Binford managers give equal weights to the performance
criteria. Which is the best alternative, as indicated by the
preference matrix method?
Rating
Performance Criteria
Product A
Product B
Product C
1. Demand uncertainty and project risk
3
9
2
2. Similarity to present products
7
8
6
10
4
8
4. Compatibility with current
manufacturing process
4
7
6
5. Competitive Strategy
4
6
5
3. Expected return on investment (ROI)
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 60
Solved Problem 2
Rating
SOLUTION
Performance Criteria
Each of the five criteria
receives a weight of 1/5
or 0.20
Product A
Product B
Product C
1. Uncertainty and risk
3
9
2
2. Similarity
7
8
6
10
4
8
4. Compatibility
4
7
6
5. Strategy
4
6
5
3. ROI
Product
Calculation
Total Score
A
(0.20 × 3) + (0.20 × 7) + (0.20 × 10) +
(0.20 × 4) + (0.20 × 4)
= 5.6
B
(0.20 × 9) + (0.20 × 8) + (0.20 × 4) +
(0.20 × 7) + (0.20 × 6)
= 6.8
C
(0.20 × 2) + (0.20 × 6) + (0.20 × 8) +
(0.20 × 6) + (0.20 × 5)
= 5.4
The best choice is product B as Products A and C are well
behind in terms of total weighted score
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 61
Solved Problem 3
Adele Weiss manages the campus flower shop. Flowers must
be ordered three days in advance from her supplier in Mexico.
Although Valentine’s Day is fast approaching, sales are almost
entirely last-minute, impulse purchases. Advance sales are so
small that Weiss has no way to estimate the probability of low
(25 dozen), medium (60 dozen), or high (130 dozen) demand for
red roses on the big day. She buys roses for $15 per dozen and
sells them for $40 per dozen. Construct a payoff table. Which
decision is indicated by each of the following decision criteria?
a. Maximin
b. Maximax
c. Laplace
d. Minimax regret
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 62
Solved Problem 3
SOLUTION
The payoff table for this problem is
Demand for Red Roses
Alternative
Low
(25 dozen)
Medium
(60 dozen)
High
(130 dozen)
Order 25 dozen
$625
$625
$625
Order 60 dozen
$100
$1,500
$1,500
($950)
$450
$3,250
$0
$0
$0
Order 130 dozen
Do nothing
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 63
Solved Problem 3
a. Under the maximin criteria, Weiss should order 25 dozen,
because if demand is low, Weiss’s profits are $625, the best
of the worst payoffs.
b. Under the maximax criteria, Weiss should order 130 dozen.
The greatest possible payoff, $3,250, is associated with the
largest order.
c. Under the Laplace criteria, Weiss should order 60 dozen.
Equally weighted payoffs for ordering 25, 60, and 130 dozen
are about $625, $1,033, and $917, respectively.
d. Under the minimax regret criteria, Weiss should order 130
dozen. The maximum regret of ordering 25 dozen occurs if
demand is high: $3,250 – $625 = $2,625. The maximum regret
of ordering 60 dozen occurs if demand is high: $3,250 –
$1,500 = $1,750. The maximum regret of ordering 130 dozen
occurs if demand is low: $625 – (–$950) = $1,575.
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 64
Solved Problem 4
White Valley Ski Resort is planning the ski lift operation for its
new ski resort and wants to determine if one or two lifts will be
necessary
Each lift can accommodate 250 people per day and skiing
occurs 7 days per week in the 14-week season and lift tickets
cost $20 per customer per day
The table below shows all the costs and probabilities for each
alternative and condition
Should the resort purchase one lift or two?
Alternatives
Conditions
One lift
Two lifts
Utilization
Installation
Operation
Bad times (0.3)
0.9
$50,000
$200,000
Normal times (0.5)
1.0
$50,000
$200,000
Good times (0.2)
1.0
$50,000
$200,000
Bad times (0.3)
0.9
$90,000
$200,000
Normal times (0.5)
1.0
$90,000
$400,000
Good times (0.2)
1.0
$90,000
$400,000
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 65
Solved Problem 4
SOLUTION
The decision tree is shown in Figure A.7. The payoff ($000) for
each alternative-event branch is shown in the following table.
The total revenues from one lift operating at 100 percent
capacity are $490,000 (or 250 customers × 98 days ×
$20/customer-day).
Payoff Calculation (Revenue – Cost)
Alternatives
Economic Conditions
One lift
Bad times
0.9(490) – (50 + 200) = 191
Normal times
1.0(490) – (50 + 200) = 240
Good times
1.0(490) – (50 + 200) = 240
Bad times
0.9(490) – (90 + 200) = 151
Normal times
1.5(490) – (90 + 400) = 245
Good times
1.9(490) – (90 + 400) = 441
Two lifts
Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall.
A – 66
Solved Problem 4
Bad times [0.3]
0.3(191) + 0.5(240) +
0.2(240) = 225.3
Normal times [0.5]
$191
$240
One lift
$225.3
$256.0
Good times [0.2]
Bad times [0.3]
Two lifts
Normal times [0.5]
$256.0
0.3(151) + 0.5(245) +
0.2(441) = 256.0
Good times [0.2]
$240
$151
$245
$441
FIGURE A.7
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A – 68