Quiz 3
1. Given: P(A) = 0.4 P(B) = 0.6 P(A OR B) = 0.91. Find P(A|B).
a. 0.24
b. 0.4
c. 0.15
d. Cannot be determined.
2. If J and K are INDEPENDENT events, then which of the following is TRUE?
a. P(J OR K) = P(J) + P(K) - P(J)*P(K)
b. P(J AND K) = 0
c. J and K are mutually exclusive events.
d. P(J OR K) = 0
3. A poll concerning credit cards found that 35 percent of respondents use a credit card that gives them one mile of air travel for every dollar they charge. Thirty percent of the respondents charge more than $2000 per month. Of those respondents who charge more than $2000, 80 percent use a credit card that gives them one mile of air travel for every dollar they charge. What is the probability that a randomly selected respondent expected to spend more than $2000 AND use a credit card that gives them a mile of air travel for every dollar they charge?
a. (0.80)(0.35)
b. (0.80)(0.30)
c. (0.30)(0.35)
d. 0.80
4. If P(J) = 0.3, P(K) = 0.6, and J and K are independent events, then:
a. P(J and K) = 0
b. P(J OR K) = 0
c. P(J) does not equal P(J|K).
d. P(J OR K) = 0.72
5. When sampling WITHOUT replacement, the second pick is
a. independent from the first pick.
b. a complement of the first pick.
c. mutually exclusive from the first pick.
d. dependent on the first pick.
6. Given: P(A) = 0.4, P(B) = 0.6, P(A OR B) = 0.65; Find P(A AND B)
a. 0.35
b. 1
c. 0.05
d. 0.24
7. In a survey at a California ski resort, 100 skiers and snowboarders of different age groups were surveyed. The information is shown in the table. Suppose one person is randomly selected. Find the probability that the person was a skier OR was age 11 - 20.
a. 77/100
b. 60/100
c. 12/100
d. 89/100
8. A poll concerning credit cards found that 35 percent of respondents use a credit card that gives them one mile of air travel for every dollar they charge. Thirty percent of the respondents charge more than $2000 per month. Of those respondents who charge more than $2000, 80 percent use a credit card that gives them one mile of air travel for every dollar they charge. What does 0.80 represent?
a. P(air miles AND charge over $2000 per month)
b. P(charge over $2000 per month | air miles)
c. P(air miles OR charge over $2000 per month)
d. P(air miles | charge over $2000 per month)
9. In a survey at a California ski resort, 100 skiers and snowboarders of different age groups were surveyed. The information is shown in the table. Suppose one person is randomly selected. Find the probability that the person was a snowboarder GIVEN he/she was age 21 - 40.
a. 40/100
b. 12/100
c. 12/40
d. 12/42
10. Given: P(A) = 0.4, P(B) = 0.6, P(A OR B) = 0.65; Which of the following is FALSE?
a. A and B are mutually exclusive.
b. P(A OR B) = P(A) + P(B) - P(A AND B)
c. P(A) = P(B')
d. A and B are dependent events.
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