D. Events A and B are exhaustive.

7. A continuous probability distribution represents a random variable

A. that has a definite probability for the occurrence of a given integer.

B. having an infinite number of outcomes that may assume any number of values within an interval.

C. having outcomes that occur in counting numbers.

D. thats best described in a histogram.

8. A basketball team at a university is composed of ten players. The team is made up of players who play the position of either guard, forward, or center. Four of the ten are guards, four are forwards, and two are centers. The numbers that the players wear on their shirts are 1, 2, 3, and 4 for the guards; 5, 6, 7, and 8 for the forwards; and 9 and 10 for the centers. The starting five are numbered 1, 3, 5, 7, and 9. Let a player be selected at random from the ten. The events are defined as follows:

Let A be the event that the player selected has a number from 1 to 8.

Let B be the event that the player selected is a guard.

Let C be the event that the player selected is a forward.

Let D be the event that the player selected is a starter.

Let E be the event that the player selected is a center.

Calculate P(C).

A. 0.40

B. 0.80

C. 0.50

D. 0.20

9. An apartment complex has two activating devices in each fire detector. One is smoke-activated and has a probability of .98 of sounding an alarm when it should. The second is a heat-sensitive activator and has a probability of .95 of operating when it should. Each activator operates independently of the other. Presume a fire starts near a detector. What is the probability that both activating devices will work properly?

A. 0.931

B. 0.049

C. 0.9895

D. 0.965

10. Which of the following is correct concerning the Poisson distribution?

A. Each event being studied must be statistically dependent on the previous event.

B. The mean is usually smaller than the variance.

C. The mean is usually larger than the variance.

D. The event being studied is restricted to a given span of time, space, or distance.

11. If the probability that an event will happen is 0.3, what is the probability of the events complement?

A. 0.1

B. 0.3

C. 1.0

D. 0.7

12. The probability of an offender having a speeding ticket is 35%, having a parking ticket is 44%, having both is 12%. What is the probability of an offender having either a speeding ticket or a parking ticket or both?

A. 91%

B. 79%

C. 55%

D. 67%

Protestant Catholic Jewish Other | ||||

Democrat | 0.35 | 0.10 | 0.03 | 0.02 |

Republican | 0.27 | 0.09 | 0.02 | 0.01 |

Independent | 0.05 | 0.03 | 0.02 | 0.01 |

13. The table above gives the probabilities of combinations of religion and political parties in a city in the United States. What is the probability that a randomly selected person will be a Protestant and at the same time be a Democrat or a Republican?

A. 0.62

B. 0.89

C. 0.35

D. 0.67

14. A breeder records probabilities for two variables in a population of animals using the two-way table given here. Given that an animal is brown-haired, what is the probability that its short-haired?

Brown-haired Blond | ||

Short-haired | 0.06 | 0.23 |

Shaggy | 0.51 | 0.20 |

A. 0.0306

B. 0.222

C. 0.06

D. 0.105

15. If event A and event B are mutually exclusive, P(A or B) =

A. P(A) + P(B) P(A and B).

B. P(A) + P(B).

C. P(A) P(B).

D. P(A + B).

16. Approximately how much of the total area under the normal curve will be in the interval spanning 2 standard deviations on either side of the mean?

A. 50%

B. 68.3%

C. 99.7%

D. 95.5%

17. Find the z-score that determines that the area to the right of z is 0.8264.

A. 1.36

B. 0.94

C. 1.36

D. 0.94

18. For each car entering the drive-through of a fast-food restaurant, x = the number of occupants. In this study, x is a

A. discrete random variable.

B. dependent event.

C. joint probability.

D. continuous quantitative variable.

19. From an ordinary deck of 52 playing cards, one is selected at random. What is the probability that the selected card is either an ace, a queen, or a three?

A. 0.25

B. 0.0769

C. 0.3

D. 0.2308

20. A credit card company decides to study the frequency with which its cardholders charge for items from a certain chain of retail stores. The data values collected in the study appear to be normally distributed with a mean of 25 charged purchases and a standard deviation of 2 charged purchases. Out of the total number of cardholders, about how many would you expect are charging 27 or more purchases in this study?

A. 94.8%

B. 15.9%

C. 47.8%

D. 68.3%