EXAM 250712
1. 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? (EXAM 250712)
A. 0.342
B. 0.239
C. 0.475
D. 0.136
2. 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. 2.1%
C. 4.2%
D. 0.3%
3. If the probability that an event will happen is 0.3, what is the probability of the event's complement?
A. 0.1
B. 1.0 C.0.7 D.0.3
4. 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. 28
B. 0
C. 10 D.22
5. If event A and event B are mutually exclusive, P(A or B) =
A. P(A) + P(B).
B. P(A + E).
C. P(A) - P(B).
D. P(A) + P(B) - P(A and B).
6. A continuous probability distribution represents a random variable
A. having an infinite number of outcomes that may assume any number of values within an interval.
B. that's best described in a histogram.
C. that has a definite probability for the occurrence of a given integer.
D. having outcomes that occur in counting numbers.
7. 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%
8. Which of the following is a discrete random variable?
A. The time required to drive from Dallas to Denver
B. The weight of football players in the NFL
C. The average daily consumption of water in a household
D. The number of three-point shots completed in a college basketball game
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
9. 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. 0.67
B. 0.35
C. 0.89
D. 0.62
10. 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{A°).
Brown haired
Blond
Short-haired
0.06
0.23
Shaggy
0.51
0.20
A. 0.77
B. 0.36
C. 0.49 D.0.51
11. In the binomial probability distribution, p stands for the
A. number of trials.
B. number of successes.
C. probability of success in any given trial.
D. probability of failure in any given trial.
12. 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. 0.9939
B. 0.1354
C. 0.0071
D. 0.0075
13. Tornadoes for January in Kansas average 3.2 per month. What is the probability that, next January, Kansas will experience exactly two tornadoes?
A. 0.2087
B. 0.4076
C. 0.1304
D. 0.2226
14. For each car entering the drive-through of a fast-food restaurant, x = the number of occupants. In this study, x is a
A. joint probability.
B. continuous quantitative variable.
C. dependent event.
D. discrete random variable.
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. 55%
B. 67%
C. 91%
D. 79%
16. 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. 47.8%
C. 68.3%
D. 15.9%
17. 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. 0.05
B. 0.00
C. 0.03
D. 0.02
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. 0.06
B. 0.105
C. 0.222
D. 0.0306
19. 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. 0.965
B. 0.9895
C. 0.931
D. 0.049
20. Consider an experiment that results in a positive outcome with probability 0.38 and a negative outcome with probability 0.62. Create a new experiment consisting of repeating the original experiment 3 times. Assume each repetition is independent of the others. What is the probability of three successes?
A. 1.14
B. 0.055
C. 0.238
D. 0.762
A. 0.342
B. 0.239
C. 0.475
D. 0.136
2. 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. 2.1%
C. 4.2%
D. 0.3%
3. If the probability that an event will happen is 0.3, what is the probability of the event's complement?
A. 0.1
B. 1.0 C.0.7 D.0.3
4. 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. 28
B. 0
C. 10 D.22
5. If event A and event B are mutually exclusive, P(A or B) =
A. P(A) + P(B).
B. P(A + E).
C. P(A) - P(B).
D. P(A) + P(B) - P(A and B).
6. A continuous probability distribution represents a random variable
A. having an infinite number of outcomes that may assume any number of values within an interval.
B. that's best described in a histogram.
C. that has a definite probability for the occurrence of a given integer.
D. having outcomes that occur in counting numbers.
7. 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%
8. Which of the following is a discrete random variable?
A. The time required to drive from Dallas to Denver
B. The weight of football players in the NFL
C. The average daily consumption of water in a household
D. The number of three-point shots completed in a college basketball game
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
9. 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. 0.67
B. 0.35
C. 0.89
D. 0.62
10. 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{A°).
Brown haired
Blond
Short-haired
0.06
0.23
Shaggy
0.51
0.20
A. 0.77
B. 0.36
C. 0.49 D.0.51
11. In the binomial probability distribution, p stands for the
A. number of trials.
B. number of successes.
C. probability of success in any given trial.
D. probability of failure in any given trial.
12. 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. 0.9939
B. 0.1354
C. 0.0071
D. 0.0075
13. Tornadoes for January in Kansas average 3.2 per month. What is the probability that, next January, Kansas will experience exactly two tornadoes?
A. 0.2087
B. 0.4076
C. 0.1304
D. 0.2226
14. For each car entering the drive-through of a fast-food restaurant, x = the number of occupants. In this study, x is a
A. joint probability.
B. continuous quantitative variable.
C. dependent event.
D. discrete random variable.
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. 55%
B. 67%
C. 91%
D. 79%
16. 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. 47.8%
C. 68.3%
D. 15.9%
17. 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. 0.05
B. 0.00
C. 0.03
D. 0.02
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. 0.06
B. 0.105
C. 0.222
D. 0.0306
19. 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. 0.965
B. 0.9895
C. 0.931
D. 0.049
20. Consider an experiment that results in a positive outcome with probability 0.38 and a negative outcome with probability 0.62. Create a new experiment consisting of repeating the original experiment 3 times. Assume each repetition is independent of the others. What is the probability of three successes?
A. 1.14
B. 0.055
C. 0.238
D. 0.762
