Transcript Slide 1
PLEASE PASS OUT YOUR
ADVISORY FOLDERS!
PROBABILITY
What do you think the chances are…?
Probability…what is it?
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) =
You try one
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?
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
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)