1. If the mean number of hours of television watched by teenagers per week is 12 with a standard deviation of 2 hours, what proportion of teenagers watch 16 to 18 hours of TV a week? (Assume a normal distribution.)
A. 4.5%
B. 4.2%
C. 0.3%
D. 2.1%
2. Let event A = rolling a 1 on a die, and let event B = rolling an even number on a die. Which of the following is correct concerning these two events?
A. On a Venn diagram, event B would contain event A.
B. On a Venn diagram, event A would overlap event B.
C. Events A and B are exhaustive.
D. Events A and B are mutually exclusive.
3. 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. 0.20
C. 0.80
D. 0.50
4. The Burger Bin fast-food restaurant sells a mean of 24 burgers an hour and its burger sales are normally distributed. If hourly sales fall between 24 and 42 burgers 49.85% of the time, the standard deviation is _______ burgers.
A. 3
B. 6
C. 9
D. 18
5. 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 it's short-haired?
Brown-haired Blond
Short-haired 0.06 0.23
Shaggy 0.51 0.20
A. 0.105
B. 0.222
C. 0.0306
D. 0.06
6. A breeder records probabilities for two variables in a population of animals using the two-way table given here. Let A be the event "shaggy and brown-haired." Compute P(Ac).
Brown-haired Blond
Short-haired 0.06 0.23
Shaggy 0.51 0.20
A. 0.51
B. 0.49
C. 0.36
D. 0.77
Brown-haired Blond
Short-haired 0.06 0.23
Shaggy 0.51 0.30
7. A breeder records probabilities for two variables in a population of animals using the two-way table given here. Let A be the event "shaggy and brown-haired." Compute P(Ac).
A. 0.77
B. 0.49
C. 0.36
D. 0.51
Brown-haired Blond
Short-haired 0.06 0.23
Shaggy 0.51 0.30
8. 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 it's short-haired?
A. 0.222
B. 0.06
C. 0.107
D. 0.0306
9. The Burger Bin fast-food restaurant sells a mean of 24 burgers an hour and its burger sales are normally distributed. What is the probability that the Burger Bin will sell 12 to 18 burgers in an hour?
A. 0.342
B. 0.136
C. 0.239
D. 0.475
10. In the binomial probability distribution, p stands for the
A. probability of failure in any given trial.
B. number of successes.
C. number of trials.
D. probability of success in any given trial.
11. Using the standard normal table on page 822 of the textbook, determine the solution for P(0.00 ≤ z ≤ 2.01).
A. 0.4778
B. 0.0222
C. 0.1179
D. 0.4821
12. Tornadoes for January in Kansas average 3.2 per month. What is the probability that, next January, Kansas will experience exactly two tornadoes?
A. 0.2226
B. 0.4076
C. 0.2087
D. 0.1304
13. 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. 15.9%
B. 68.3%
C. 94.8%
D. 47.8%
14. 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. 0.049
B. 0.931
C. 0.9895
D. 0.965
15. 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. 67%
B. 91%
C. 55%
D. 79%
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
16. 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. 0.67
D. 0.35
17. Assume that an event A contains 10 observations and event B contains 15 observations. If the intersection of events A and B contains exactly 3 observations, how many observations are in the union of these two events?
A. 22
B. 0
C. 10
D. 28
18. Find the z-score that determines that the area to the right of z is 0.8264. End of exam
A. 1.36
B. -0.94
C. -1.36
D. 0.94
19. 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. 99.7%
B. 50%
C. 68.3%
D. 95.5%
20. The area under the normal curve extending to the right from the midpoint to z is 0.17. Using the standard normal table on the textbook's back endsheet, identify the relevant z value.
A. 0.0675
B. -0.0675
C. 0.4554
D. 0.44