Questions 1 to 20: Select the best answer to each question. Note that a question and its answers may be split across a page break, so be sure that you have seen the entire question and all the answers before choosing an answer.
1. 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. 68.3%
B. 99.7%
C. 50%
D. 95.5%
2. Using the standard normal table in the textbook, determine the solution for P(0.00 ≤ z ≤ 2.01).
A. 0.0222
B. 0.4778
C. 0.4821
D. 0.1179
3. 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. 79%
B. 91%
C. 67%
D. 55%
4. 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. 2.1%
B. 4.2%
C. 4.5%
D. 0.3%
5. Each football game begins with a coin toss in the presence of the captains from the two opposing teams. (The winner of the toss has the choice of goals or of kicking or receiving the first kickoff.) A particular football team is scheduled to play 10 games this season. Let x = the number of coin tosses that the team captain wins during the season. Using the appropriate table in your textbook, solve for P(4 ≤ x ≤ 8).
A. 0.246
B. 0.377
C. 0.817
D. 0.171
6. 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. 28
C. 10
D. 0
7. 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.
8. 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. 6
B. 9
C. 3
D. 18
9. What is the value of ?
A. 1.6
B. 6720
C. 56
D. 336
10. 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. 0.50
C. 0.20
D. 0.80
11. For each car entering the drive-through of a fast-food restaurant, x = the number of occupants. In this study, x is a
A. dependent event.
B. discrete random variable.
C. continuous quantitative variable.
D. joint probability.
12. 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. 47.8%
B. 15.9%
C. 94.8%
D. 68.3%
13. 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 event being studied is restricted to a given span of time, space, or distance.
C. The mean is usually larger than the variance.
D. The mean is usually smaller than the variance.
14. Which of the following is a discrete random variable?
A. The weight of football players in the NFL
B. The average daily consumption of water in a household
C. The time required to drive from Dallas to Denver
D. The number of three-point shots completed in a college basketball game
15. 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. 0.4554
C. 0.44
D. 0.0675
16. If the probability that an event will happen is 0.3, what is the probability of the event's complement?
A. 1.0
B. 0.1
C. 0.7
D. 0.3
17. A new car salesperson knows that she sells a car to one customer out of 20 who enter the showroom. Find the probability that she'll sell a car to exactly two of the next three customers.
A. 0.0075
B. 0.0071
C. 0.9939
D. 0.1354
18. 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. 0.0306
B. 0.105
C. 0.222
D. 0.06
19. The Burger Bin fast-food restaurant sells a mean of 24 burgers an hour and its burger sales are normally distributed. The standard deviation is 6. What is the probability that the Burger Bin will sell 12 to 18 burgers in an hour?
A. 0.475
B. 0.239
C. 0.342
D. 0.136
20. The possible values of x in a certain continuous probability distribution consist of the infinite number of values between 1 and 20. Solve for P(x = 4).
A. 0.02
B. 0.00
C. 0.05
D. 0.03