Transcript m162-9

Betting
By Billy Lai and Charlie Law
Probability
and
Percentage
Gambling is the wager of something of material value on
an event with an uncertain outcome with the primary
intent of winning additional material goods
Presentation Outline
Expected value
 Pari-mutuel betting


Mark Six -- Background

Lottery Betting

Organized by the Hong
Kong Jockey Club
(HKJC) Since 1975

3 Times a Week
(Tuesday, Thursday and
Saturday or Sunday)
Hong Kong Jockey Club
(香港賽馬會)

Non-profit organization founded in1884

Provides betting entertainment in HK
such as horse racing and Mark Six

Largest taxpayer (~$1billion each year)
What is Mark Six?

Lottery Style Game with 49 colored
balls numbered from 1 to 49

In each game, 7 balls are drawn from
these 49 balls

Name of First Six Numbers Drawn:
Drawn Number
Name of Last One Drawn:
Extra Number
Rules Of Mark Six

Rule 1:
Choose 6 out of
49 numbers

Rule2:
Wager $10 on
each Selection
For example, in the ticket,
Selection 1:
Selection 2:

Total wager :
$10 x = $ 0
http://www.youtube.com/w
atch?v=DFYSUX-L9jU
Ticket of Mark Six
Prize Qualification
Name of
Prize
Condition
Payout
1st Prize
Pick all the 6 Drawn
Numbers
Total number of winning unit investments
in the First Division Prize.
Minimum First Division Prize Fund:
$ 8 millions
2nd
Prize
Pick 5 Drawn Numbers +
Extra Number
Total number of winning unit investments
in the Second Division Prize
3rd
Prize
Pick 5 Drawn Numbers
Total number of winning unit investments
in the Third Division Prize
4th Prize
Pick 4 Drawn Numbers +
Extra Number
$ 9600
5th Prize
Pick 4 Drawn Numbers
$ 640
6th Prize
Pick 3 Drawn Numbers +
Extra Number
$ 320
7th Prize
Pick 3 Drawn Numbers
$ 40
What is the winning probability?

Example. (winning probability of 6th prize[3 Drawn
Numbers + Extra Number])

Number of possible way to buy a selection:
C 649

Number of possible way to win 6th prize:
C36  C11  C242

Winning probability of 6th prize:
C36  C242
C649

17,220
 1.2314103
13,983,816
Remarks:
nCr 
n!
(n  r )!r!
Winning Probability
Name of Prize
1st Prize
Probability
1

C 649
2nd Prize
C56
C649
3rd Prize
1
 7.1511 108
13,983,816

1
 4.2907 10 7
2,330,636
C56  C142
C649
4th Prize
C46  C142
C649
5th Prize
C46  C242
C649
6th Prize
C36  C242
C649
7th Prize

252
 1.8021105
13,983,816

630
 4.5052105
13,983,816

12915
 9.235710 4
13,983,816

17,220
 1.2314103
13,983,816
C36  C342
229,600

 0.01642
C649
13,983,816
Question
The Prize Qualification on 17/2/2011 is
listed below, What is the expected value of
the winnings of one selection?
A:E(X)=>10
B:
7.5<E(X)<10
C:
5<E(X)<=7.5
D:
2.5<E(X)<=5
E:
0<E(X)<=2.5
Name of Prize
Prize
1st Prize
$23,115,220
2nd Prize
$1,165,120
3rd Prize
$73,100
4th Prize
$ 9600
5th Prize
$ 640
6th Prize
$ 320
7th Prize
$ 40
Expected Value

Expected Value ( denoted by E[X] )
is the average value an experiment is expected to
produce if it is repeated a large number of times.

E[ X ] 

xi pi
i 1
where x i is the amount of payout of the (i)th
prize and
pi is the probability of getting the (i)th prize
Example (Expected Value of Mark Six)

Tips: E[ X ]   xi pi
What is the answer?
i 1
Ans:
Name of Prize
Prize
= (1st Prize) x (Probability of 1st Prize) +
1st Prize
$23,115,220
(2nd Prize) x (Probability of 2nd Prize) +
2nd Prize
$1,165,120
(3rd Prize) x (Probability of 3rd Prize) +
3rd Prize
$73,100
(4th Prize) x (Probability of 4th Prize) +
4th Prize
$ 9600
(5th Prize) x (Probability of 5th Prize) +
5th Prize
$ 640
6th Prize
$ 320
7th Prize
$ 40
E(X)
(6th Prize) x (Probability of 6th Prize) +
(7th Prize) x (Probability of 7th Prize)
8
7
 23115220 7.151110  1165120 4.290710
 73100 1.8020105  9600 4.5052 105
 640 9.2357 10 4  320 0.001231 40 0.01642
= $5.5446
< $10 which is the wager!!!
Pari-mutuel
Game – Horse Racing
Instructions:
 Two people (or one person if necessary)
in a group
 Each group receives a paper on which
there is an amount you can wager on 1
out of the 4 horses provided
 Place your paper into the collection box
Assumptions
You guys are basically gambling addicts so
please wager every penny you have on
one horse 
 One group can only wager on one horse

How to calculate the payout?
Calculate:
 Total Pool (TP)
 The amount wagered on the winning
horse (W)
 Then, the payout (P) (per $1 wagered)
TP
P
W
Assumptions Made
The operator does not make any profit
i.e. TP is distributed to all winners
Reality
In reality, the operator usually takes away
a certain percentage of the TP as the
commission
 In Hong Kong, under the Betting Duty
Ordinance (BDO), the duty accounts for
a certain percentage of the proceeds
from horse racing

The distribution of Proceeds from
Horse Racing
Type of Bet
Duty
Standard Horse Racing
Bets
12%
Dividends to winners
≥82.5%
HKJC’s Commission
≤5.5%
Total
100%
Payout distributed By the HKJC
Calculate:
 Total Pool (TP)
 The amount wagered on the winning
horse (W)
 Commission (C) and Duty (D)
 Then, the payout (P) (per $1 wagered)
TP  C  D
P
W
An extract from the HKJC’s website
concerning place betting:

The Net Pool will be divided into two or
three parts, according to whether two
Place Betting or three Place Betting is
being conducted, then each such divided
part will be divided by the number of Unit
Bets on the horse to which the divided
part relates.
The Inventor
Joseph Oller
Invented pari-mutuel betting in 1867
 Sentenced to prison in 1874
 Pari-mutuel betting system legalized by
the French authorities in 1891
 Focused on the entertainment industry
from 1876

Places He Owned:
Places He Owned:
Additional Information
The website of the HKJC:
 http://www.hkjc.com/english/betting/betti
ng_rule.htm

Homework(Question1)

Based on the Prize Qualification of Mark Six
on 17/02/2011, Calculate the expected income
(expected value) of the Jockey Club if the total
turnover is $ 46,613,470.
Name of Prize
Prize
1st Prize
$23,115,220
2nd Prize
$1,165,120
3rd Prize
$73,100
4th Prize
$ 9600
5th Prize
$ 640
6th Prize
$ 320
7th Prize
$ 40
Homework(Question2)

Using the figures in the game (which will
be provided in the uploaded ppt),
calculate the rate of payout if the game
was organized by the HKJC, given the
commission is 5.5% of TP
Horses
Wager
Horse 1
$100
Horse 2
$1200
Horse 3
$1900
Horse 4
$1200
Homework (Extra Credit Problem)

Given that the total turnovers in a Mark
Six game and a horse racing game are the
same and the prize qualification of both
games and the BDO(in P.18) are the same
as shown in questions 1 and 2. Then, from
which game, Mark Six or horse racing,
does the Hong Kong Jockey Club receive
more commission? State your reasons.
The End