1. PROBABILITY
Lesson 10.3A

2. Sample SPACE The set of all possible outcomes of an experiment
Example: roll a die once
Sample Space = {1,2,3,4,5,6}
Example: toss a coin twice
Sample Space = {HH, TH, HT, TT}
Discuss equally likely events. (Spinner)

3. Probability
P(event) = # 𝑜𝑓 𝑤𝑎𝑦𝑠 𝑒𝑣𝑒𝑛𝑡 𝑐𝑎𝑛 𝑜𝑐𝑐𝑢𝑟 # 𝑜𝑢𝑡𝑐𝑜𝑚𝑒𝑠 𝑖𝑛 𝑠𝑎𝑚𝑝𝑙𝑒 𝑠𝑝𝑎𝑐𝑒
if the events are all equally likely.
What is the possible range of value for P(event)?

4. Simple Probability
What is the probability of rolling a 5 on a standard die? A number greater than 2?
What is the probability of getting two tails when you toss a coin twice?
What is the probability of drawing a facecard from a standard deck of cards?
What is the probability of that a random student’s birthday falls on Tuesday this year?

5. Conditional Probability
We surveyed 100 people. The results are below.
Ride a Motorcycle Don’t Ride
Male
Female
a) What is the probability that a person in our survey rides a motorcycle?
b) What is the probability that a male rides a motorcycle?
c) What is the probability that a motorcyclist is male?

6. Find the probability that a point in the figure lies in the white area.

7. Odds Favorable outcomes/unfavorable outcomes Find the odds of
Getting heads when tossing a coin
Rolling a 4 or a 5 on a die
Drawing a card and getting a queen

8. USING Counting PRINCIPLES
Find the probability of getting all hearts in a five card poker hand.
5 boys and 3 girls are in a drawing for three prizes. Find the probability that 3 boys win.