Transcript Slide 1

PLEASE PASS OUT YOUR
ADVISORY FOLDERS!
PROBABILITY
What do you think the chances are…?
Probability…what is it?
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Probability is the chance of an event occurring.
Its value ranges from 0 to 1.
0 means – not going to happen
1 means – always will happen
We find probability by measuring what we want to
happen and putting it over the total outcomes that
can happen
Example
A number cube, which is how dice is referred to as
on the PSSA, is rolled. What is the probability we
roll an odd number?
 How many odd numbers are on a number cube?
 How many total numbers (outcomes) are on a
number cube?
P(odd) =
We can reduce this fraction
P(odd) =
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You try one
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A bag of marbles contains 8 red, 5 blue, 1 black,
and 2 green marbles. What is the probability of
selecting a green marble?
A)
B)
C)
D)
What if two or more things need to
happen?
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Find the probability of each individual event.
If they need to happen together, find the product of
the events.
Formula: P(event #1) • P(event #2) = P(both events)
Example
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Find the probability of flipping a coin and getting
heads while rolling a number greater than 4 on a
number cube.
P(heads) =
P(greater than 4) =
P(heads and greater than 4) =
You try one
 Find
the probability of spinning a red on the spinner and
rolling an even number?
A)
B)
C)
D)