1. 13-5 Conditional Probability

2. Conditional Probability
The probability of an event under the condition that some preceding event has occurred
P(A l B)=P(A and B)
P(B)
P(B) is usually following “given that…”

3. Conditional Probability
1) You toss two coins. What is the probability that you toss two heads given that you have tossed at least 1 head?
P(A) = The two coins come up heads
P(B) = There is a least one head
Different outcomes of two coins?
(H,H)-(T,H)-(H,T)-(T,T)

4. 2) A neighborhood lets families have two pets
2) A neighborhood lets families have two pets. They can have two dogs, two cats, or one of each. What is the probability that the family will have exactly 2 cats if one pet is a cat?
Sample space:
P(A) = Two cats =
P(B) = At least one cat=
P (A l B) =

5. 3) Two number cubes are tossed
3) Two number cubes are tossed. Find the probability that the numbers showing on the cubes match given that their sum is greater than five.

6. 4) One card is drawn from a standard deck of cards
4) One card is drawn from a standard deck of cards. What is the probability that it is a queen given that it is a face card?