Events and Independence

If A and B are independent, which statement must be true?

• P(A∩B) = 0

• P(A|B) = P(A)

• P(A∪B) = 0

• P(A) + P(B) = 1

What is the probability that a student does play a sport given they do not play an instrument? 

• .2

• .2222

• .10

• .5

What is the probability that a student plays on a sports team given they play an instrument?

• .7273

• .8

• .55

• .2222

Are the events "Sports" and "Community Service" independent?

• Yes, because P(S) is the same as P(S|CS).

• No, because P(S) is not the same as P(S|CS).

• Yes, because P(S) is the same as P(CS|S).

• No, because P(S) is not the same as P(CS|S).

• What is the probability of a student who does community service and does not play sports?

• What is the probability of a student who does community service given that they do not play sports?

• What is the probability of a student who does not play sports given that they do not do community service?

• What is the probability of a student who does not play sports or does not do community service?

Suppose the P(A) = .55, P(B) = .30 and P(A and B) = .12, find P(A or B).

• 0.85

• 0.165

• 0.12

• 0.73

Find P(Sophomore |Pass)

• 17/20

• 17/50

• 9/25

• 3/20

Find P(Sophomore U Pass)

• 53/60

• 70/60

• 5/6

If A and B are mutually exclusive, which statement below must be true?

• P(A∩B) = 0

• P(A|B) = 0

• P(A∪B) = 0

• P(A) + P(B) = 1

What is the probability that the person picked will be a boy given they speak german? 

• .7273

• .4

• .16

• .22