AP Stats Chapter 5

A die is weighted so that when it is rolled, an odd number will come up twice as often as an even number in the long run. Which of the following is a legitimate assignment of probabilities to the outcomes in the sample space that is consistent with the description of the die?

• A

• B

• C

• D

• None of the above

In a survey of 100 students selected at random from those enrolled at a small liberal arts college, the following data were obtained. Each student was asked how much time he or she spent on the Internet during a typical day, and gender was also noted. Assume that this data is representative of students at this college. What is the approximate probability that a randomly selected student at this college is a female who spends no time on the Internet in a typical day?

• 10/10

• 10/15

• 10/25

• 10/35

• 10/100

If a randomly selected student is male, what is the approximate probability that he spends hour or more on the Internet in a typical day?

• 30/30

• 30/40

• 30/65

• 35/65

• 30/100

Under what conditions is it true that P(A OR B) = P(A) + P(B) ?

• A and B must be mutually exclusive.

• A and B cannot be mutually exclusive.

• A and B must be independent.

• A and B must be both mutually exclusive and independent.

• No conditions are required. It is always true that P(A OR B) = P(A) + P(B)

Under what conditions is it true that P(A AND B) = P(B|A)P(A) ?

• A and B must be mutually exclusive.

• A and B cannot be mutually exclusive.

• A and B must be independent.

• A and B must be both mutually exclusive and independent.

• No conditions are required. It is always true that P(A AND B) = P(B|A)P(A) ?

A statistics class consists of 30 males and 20 females. Ten of the males and ten of the females are also currently enrolled in a science course.

If a student is selected at random from those enrolled in this statistics class, what is the probability that a female is selected?

• .1

• .2

• .4

• .5

• .6

A statistics class consists of 30 males and 20 females. Ten of the males and ten of the females are also currently enrolled in a science course.

If a student is selected at random from those enrolled in this statistics class, what is the probability that the selected student is a male who is also enrolled in a science course?

• .1

• .2

• .4

• .5

• .6

A statistics class consists of 30 males and 20 females. Ten of the males and ten of the females are also currently enrolled in a science course.

A student is selected at random from those enrolled in this statistics class. Given that the selected student is female, what is the probability that she is enrolled in a science course?

• .1

• .2

• .4

• .5

• .6

Sixty percent of the students at an urban university carry more than one credit card. Selecting a student at random from the students at this university can be viewed as a chance experiment with two possible outcomes: has more than one credit card and does not have more than one credit card. Which of the following would be a correct assignment of random digits to the outcomes in order to simulate selecting a student at random from the students enrolled at the university?

• A. 0 represents more than one credit card, 1 represents not more than one credit card; ignore all other digits

• B. Odd digits represent more than one credit card, and even digits represent not more than one credit card.

• C. 0, 1, 2, 3 represent more than one credit card; and 4,5,6,7,8, 9 represent more than on credit card

• D. 0, 1, 2, 3, 4, and 5 represent more than one credit card; and 6, 7, 8, 9 represent not more than one credit chard

• E. C and D both represent correct assignments.

Which of the following would be a correct assignment of random digits to the outcomes of heads and tails in order to simulate the flip of a fair coin?

• A. 0 represents heads, 1 represents tails; ignore all other digits.

• B. Odd digits represent heads, even digits represent tails.

• C. 0, 1, 2, 3, and 4 represent heads & 5, 6, 7, 8, and 9 represent tails

• Only B and C above are correct.

• A, B, and C above are all correct.