1. 12- 8 Probability of Compound Events
Objective: Find probabilities of exclusive and overlapping events and independent and dependent

2. 12- 8 Probability of Compound Events
Is the possibility of two or more events linked with the word
And or the word OR.

3. 12- 8 Probability of Compound Events
Mutually exclusive: can’t happen at same time
P(A or B) = P(A) + P(B)
Overlapping events can happen at same time
P(A or B) = P(A) + P(B) – P(A and B)

4. 12- 8 Probability of Compound Events
Spinner has 20 sections numbered 1 to 10.
Probability of spinning a 2 or a 5?
Can’t land on both at same time so events are exclusive.
P(2 or 5) = P(2) + P(5)

5. 12- 8 Probability of Compound Events
Spinner has 20 sections numbered 1 to 10.
Probability of spinning a multiple of 2 or a 5?
Since a number can be a multiple of 2 and of 5, such as 10, The events are overlapping.
P(Multiples of 2 or 5) =
P(multi 2) + P(multi 5) – P(both) =
Simplify

6. 12- 8 Probability of Compound Events
Independent events if the occurrence of one event does not effect the other.
P(A and B) = P(A) ∙ P(B)

7. 12- 8 Probability of Compound Events
Roll a red cube and a blue cube. What is probability of rolling a 3 on red and even on blue?
P(3 on red) = P(even on blue) = = 1 2
P(both) = ∙ =

8. 12- 8 Probability of Compound Events
Two events are dependent if one event affects the probability of the second event. Choose and NOT replace the object.
A and B are dependent events;
P(A then B) = P(A) ∙ P(B after A)

9. 12- 8 Probability of Compound Events
GRIDDED RESPONSE is on tiles.
Without replacing the first tile, you select a second. What is the probability that you choose a R the first selection and a D the second.
P(R then D) = P(R) ∙ P(D after R)
= ∙ =

10. 12- 8 Probability of Compound Events
GRIDDED RESPONSE is on tiles.
Without replacing the first tile, you select a second. What is the probability that you choose a D the first selection and a D the second.
P(D then D) = P(D) ∙ P(D after R)
= ∙ =

11. 12- 8 Probability of Compound EventsHW
p. 780
9 - 27
Every third