CH4 QBA

1. Each individual outcome of an experiment is called
a. the sample space
b. a sample point
c. an experiment
d. an individual

B

2. The collection of all possible sample points in an experiment is
a. the sample space
b. a sample point
c. an experiment
d. the population

A

3. A graphical method of representing the sample points of an experiment is
a. a frequency polygon
b. a histogram
c. an ogive
d. a tree diagram

D

4. An experiment consists of selecting a student body president and vice president. All undergraduate students (freshmen through seniors) are eligible for these offices. How many sample points (possible outcomes as to the classifications) exist?
a. 4
b. 16
c. 8
d. 32

B

5. Any process that generates well-defined outcomes is
a. an event
b. an experiment
c. a sample point
d. a sample space

B

6. The sample space refers to
a. any particular experimental outcome
b. the sample size minus one
c. the set of all possible experimental outcomes
d. an event

C

7. In statistical experiments, each time the experiment is repeated
a. the same outcome must occur
b. the same outcome can not occur again
c. a different outcome may occur
d. a different out come must occur

C

8. When the assumption of equally likely outcomes is used to assign probability values, the method used to assign probabilities is referred to as the
a. relative frequency method
b. subjective method
c. probability method
d. classical method

D

9. The counting rule that is used for counting the number of experimental outcomes when n objects are selected from a set of N objects where order of selection is not important is called
a. permutation
b. combination
c. multiple step experiment
d. None of these alternatives is correct.

B

10. The counting rule that is used for counting the number of experimental outcomes when n objects are selected from a set of N objects where order of selection is important is called
a. permutation
b. combination
c. multiple step experiment
d. None of these alternatives is correct.

A

11. From a group of six people, two individuals are to be selected at random. How many possible selections are possible?
a. 12
b. 36
c. 15
d. 8

C

12. When the results of experimentation or historical data are used to assign probability values, the method used to assign probabilities is referred to as the
a. relative frequency method
b. subjective method
c. classical method
d. posterior method

A

13. A method of assigning probabilities based upon judgment is referred to as the
a. relative method
b. probability method
c. classical method
d. subjective method

D

14. A sample point refers to the
a. numerical measure of the likelihood of the occurrence of an event
b. set of all possible experimental outcomes
c. individual outcome of an experiment
d. sample space

C

15. A graphical device used for enumerating sample points in a multiple-step experiment is a
a. bar chart
b. pie chart
c. histogram
d. None of these alternatives is correct.

D

16. The intersection of two mutually exclusive events
a. can be any value between 0 to 1
b. must always be equal to 1
c. must always be equal to 0
d. can be any positive value

C

17. Two events are mutually exclusive
a. if their intersection is 1
b. if they have no sample points in common
c. if their intersection is 0.5
d. None of these alternatives is correct.

B

18. The range of probability is
a. any value larger than zero
b. any value between minus infinity to plus infinity
c. zero to one
d. any value between -1 to 1

C

19. Which of the following statements is always true?
a. -1 P(Ei) 1
b. P(A) = 1 – P(Ac)
c. P(A) + P(B) = 1
d. P 1

B

20. Events that have no sample points in common are
a. independent events
b. posterior events
c. mutually exclusive events
d. complements

C

21. Initial estimates of the probabilities of events are known as
a. sets
b. posterior probabilities
c. conditional probabilities
d. prior probabilities

D

22. Two events with nonzero probabilities
a. can be both mutually exclusive and independent
b. can not be both mutually exclusive and independent
c. are always mutually exclusive
d. are always independent

B

23. Two events, A and B, are mutually exclusive and each have a nonzero probability. If event A is known to occur, the probability of the occurrence of event B is
a. one
b. any positive value
c. zero
d. any value between 0 to 1

C

24. The addition law is potentially helpful when we are interested in computing the probability of
a. independent events
b. the intersection of two events
c. the union of two events
d. conditional events

C

25. The sum of the probabilities of two complementary events is
a. Zero
b. 0.5
c. 0.57
d. 1.0

D

26. Events A and B are mutually exclusive if their joint probability is
a. larger than 1
b. less than zero
c. zero
d. infinity

C

27. The set of all possible outcomes of an experiment is
a. an experiment
b. an event
c. the population
d. the sample space

D

28. Assuming that each of the 52 cards in an ordinary deck has a probability of 1/52 of being drawn, what is the probability of drawing a black ace?
a. 1/52
b. 2/52
c. 3/52
d. 4/52

B

29. If a dime is tossed four times and comes up tails all four times, the probability of heads on the fifth trial is
a. smaller than the probability of tails
b. larger than the probability of tails
c. 1/2
d. 1/32

C

30. If a six sided die is tossed two times and "3" shows up both times, the probability of "3" on the third trial is
a. much larger than any other outcome
b. much smaller than any other outcome
c. 1/6
d. 1/216

C

31. If A and B are independent events with P(A) = 0.65 and P(A B) = 0.26, then, P(B) =
a. 0.400
b. 0.169
c. 0.390
d. 0.650

A

32. If P(A) = 0.4, P(B | A) = 0.35, P(A B) = 0.69, then P(B) =
a. 0.14
b. 0.43
c. 0.75
d. 0.59

B

33. Of five letters (A, B, C, D, and E), two letters are to be selected at random. How many possible selections are possible?
a. 20
b. 7
c. 5!
d. 10

D

34. Given that event E has a probability of 0.31, the probability of the complement of event E
a. cannot be determined with the above information
b. can have any value between zero and one
c. 0.69
d. is 0.31

C

35. Three applications for admission to a local university are checked, and it is determined whether each applicant is male or female. The number of sample points in this experiment is
a. 2
b. 4
c. 6
d. 8

D

36. Assume your favorite soccer team has 2 games left to finish the season. The outcome of each game can be win, lose or tie. The number of possible outcomes is
a. 2
b. 4
c. 0036
d. 9

D

37. Each customer entering a department store will either buy or not buy some merchandise. An experiment consists of following 3 customers and determining whether or not they purchase any merchandise. The number of sample points in this experiment is
a. 2
b. 4
c. 6
d. 8

D

38. An experiment consists of tossing 4 coins successively. The number of sample points in this experiment is
a. 16
b. 8
c. 4
d. 2

A

39. An experiment consists of three steps. There are four possible results on the first step, three possible results on the second step, and two possible results on the third step. The total number of experimental outcomes is
a. 9
b. 14
c. 24
d. 36

C

40. Since the sun must rise tomorrow, then the probability of the sun rising tomorrow is
a. much larger than one
b. zero
c. infinity
d. None of these alternatives is correct.

D

41. If two events are independent, then
a. they must be mutually exclusive
b. the sum of their probabilities must be equal to one
c. their intersection must be zero
d. None of these alternatives is correct.

D

42. Bayes’ theorem is used to compute
a. the prior probabilities
b. the union of events
c. intersection of events
d. the posterior probabilities

D

43. On a December day, the probability of snow is .30. The probability of a "cold" day is .50. The probability of snow and "cold" weather is .15. Are snow and "cold" weather independent events?
a. only if given that it snowed
b. no
c. yes
d. only when they are also mutually exclusive

C

44. One of the basic requirements of probability is
a. for each experimental outcome Ei, we must have P(Ei) 1
b. P(A) = P(Ac) – 1
c. if there are k experimental outcomes, then P(Ei) = 1
d. P(Ei) 1

C

45. The symbol shows the
a. union of events
b. intersection of two events
c. sum of the probabilities of events
d. sample space

B

46. The symbol shows the
a. union of events
b. intersection of two events
c. sum of the probabilities of events
d. sample space

A

47. The multiplication law is potentially helpful when we are interested in computing the probability of
a. mutually exclusive events
b. the intersection of two events
c. the union of two events
d. conditional events

B

48. If two events are mutually exclusive, then their intersection
a. will be equal to zero
b. can have any value larger than zero
c. must be larger than zero, but less than one
d. will be one

A

49. The union of events A and B is the event containing all the sample points belonging to
a. B or A
b. A or B
c. A or B or both
d. A or B, but not both

C

50. If a penny is tossed three times and comes up heads all three times, the probability of heads on the fourth trial is
a. zero
b. 1/16
c. 1/2
d. larger than the probability of tails

C

51. If a coin is tossed three times, the likelihood of obtaining three heads in a row is
a. zero
b. 0.500
c. 0.875
d. 0.125

D

52. The union of two events with nonzero probabilities
a. cannot be less than one
b. cannot be one
c. could be larger than one
d. None of these alternatives is correct.

D

53. If P(A) = 0.5 and P(B) = 0.5, then P(A B)
a. is 0.00
b. is 1.00
c. is 0.5
d. None of these alternatives is correct.

D

54. If A and B are independent events with P(A) = 0.4 and P(B) = 0.6, then P(A B) =
a. 0.76
b. 1.00
c. 0.24
d. 0.20

C

55. If A and B are independent events with P(A) = 0.2 and P(B) = 0.6, then P(A B) =
a. 0.62
b. 0.12
c. 0.60
d. 0.68

D

56. If A and B are independent events with P(A) = 0.05 and P(B) = 0.65, then P(A B) =
a. 0.05
b. 0.0325
c. 0.65
d. 0.8

A

57. If A and B are mutually exclusive events with P(A) = 0.3 and P(B) = 0.5, then P(A B) =
a. 0.30
b. 0.15
c. 0.00
d. 0.20

C

58. If A and B are mutually exclusive events with P(A) = 0.3 and P(B) = 0.5, then P(A B) =
a. 0.00
b. 0.15
c. 0.8
d. 0.2

C

59. A lottery is conducted using three urns. Each urn contains chips numbered from 0 to 9. One chip is selected at random from each urn. The total number of sample points in the sample space is
a. 30
b. 100
c. 729
d. 1,000

D

60. Of the last 100 customers entering a computer shop, 25 have purchased a computer. If the classical method for computing probability is used, the probability that the next customer will purchase a computer is
a. 0.25
b. 0.50
c. 1.00
d. 0.75

B

61. Events A and B are mutually exclusive with P(A) = 0.3 and P(B) = 0.2. Then, P(Bc) =
a. 0.00
b. 0.06
c. 0.7
d. 0.8

D

62. An experiment consists of four outcomes with P(E1) = 0.2, P(E2) = 0.3, and P(E3) = 0.4. The probability of outcome E4 is
a. 0.500
b. 0.024
c. 0.100
d. 0.900

C

63. Events A and B are mutually exclusive. Which of the following statements is also true?
a. A and B are also independent.
b. P(A B) = P(A)P(B)
c. P(A B) = P(A) + P(B)
d. P(A B) = P(A) + P(B)

C

64. A six-sided die is tossed 3 times. The probability of observing three ones in a row is
a. 1/3
b. 1/6
c. 1/27
d. 1/216

D

65. The probability of the occurrence of event A in an experiment is 1/3. If the experiment is performed 2 times and event A did not occur, then on the third trial event A
a. must occur
b. may occur
c. could not occur
d. has a 2/3 probability of occurring

B

66. A perfectly balanced coin is tossed 6 times, and tails appears on all six tosses. Then, on the seventh trial
a. tails can not appear
b. heads has a larger chance of appearing than tails
c. tails has a better chance of appearing than heads
d. None of these alternatives is correct.

D

67. In an experiment, events A and B are mutually exclusive. If P(A) = 0.6, then the probability of B
a. cannot be larger than 0.4
b. can be any value greater than 0.6
c. can be any value between 0 to 1
d. cannot be determined with the information given

A

68. The set of all possible sample points (experimental outcomes) is called
a. a sample
b. an event
c. the sample space
d. a population

C

69. A method of assigning probabilities which assumes that the experimental outcomes are equally likely is referred to as the
a. objective method
b. classical method
c. subjective method
d. experimental method

B

70. A method of assigning probabilities based on historical data is called the
a. classical method
b. subjective method
c. relative frequency method
d. historical method

C

71. The probability assigned to each experimental outcome must be
a. any value larger than zero
b. smaller than zero
c. at least one
d. between zero and one

D

72. If P(A) = 0.58, P(B) = 0.44, and P(A B) = 0.25, then P(A B) =
a. 1.02
b. 0.77
c. 0.11
d. 0.39

B

73. If P(A) = 0.50, P(B) = 0.60, and P(A B) = 0.30, then events A and B are
a. mutually exclusive events
b. not independent events
c. independent events
d. not enough information is given to answer this question

C

74. If P(A) = 0.62, P(B) = 0.47, and P(A B) = 0.88, then P(A B) =
a. 0.2914
b. 1.9700
c. 0.6700
d. 0.2100

D

75. If P(A) = 0.68, P(A B) = 0.91, and P(A B) = 0.35, then P(B) =
a. 0.22
b. 0.09
c. 0.65
d. 0.58

D

76. If A and B are independent events with P(A) = 0.4 and P(B) = 0.25, then P(A B) =
a. 0.65
b. 0.55
c. 0.10
d. 0.75

B

77. If a penny is tossed three times and comes up heads all three times, the probability of heads on the fourth trial is
a. smaller than the probability of tails
b. larger than the probability of tails
c. 1/16
d. 1/2

D

78. If P(A) = 0.50, P(B) = 0.40, then, and P(A B) = 0.88, then P(B A) =
a. 0.02
b. 0.03
c. 0.04
d. 0.05

C

79. If A and B are independent events with P(A) = 0.38 and P(B) = 0.55, then P(A B) =
a. 0.209
b. 0.000
c. 0.550
d. 0.38

D

80. If X and Y are mutually exclusive events with P(X) = 0.295, P(Y) = 0.32, then P(X Y) =
a. 0.0944
b. 0.6150
c. 1.0000
d. 0.0000

D

81. If a six sided die is tossed two times, the probability of obtaining two "4s" in a row is
a. 1/6
b. 1/36
c. 1/96
d. 1/216

B

82. If A and B are independent events with P(A) = 0.35 and P(B) = 0.20, then, P(A B) =
a. 0.07
b. 0.62
c. 0.55
d. 0.48

D

83. If P(A) = 0.7, P(B) = 0.6, P(A B) = 0, then events A and B are
a. not mutually exclusive
b. mutually exclusive
c. independent events
d. complements of each other

B

84. If P(A) = 0.45, P(B) = 0.55, and P(A B) = 0.78, then P(A B) =
a. zero
b. 0.45
c. 0.22
d. 0.40

D

85. If P(A) = 0.48, P(A B) = 0.82, and P(B) = 0.54, then P(A B) =
a. 0.3936
b. 0.3400
c. 0.2000
d. 1.0200

C

86. Some of the CDs produced by a manufacturer are defective. From the production line, 5 CDs are selected and inspected. How many sample points exist in this experiment?
a. 10
b. 25
c. 30
d. 32

D

87. An experiment consists of selecting a student body president, vice president, and a treasurer. All undergraduate students, freshmen through seniors, are eligible for the offices. How many sample points (possible outcomes as to the classifications) exist?
a. 12
b. 16
c. 64
d. 100

C

88. Six applications for admission to a local university are checked, and it is determined whether each applicant is male or female. How many sample points exist in the above experiment?
a. 64
b. 32
c. 16
d. 4

A

89. Assume your favorite soccer team has 3 games left to finish the season. The outcome of each game can be win, lose, or tie. How many possible outcomes exist?
a. 7
b. 27
c. 36
d. 64

B

90. Each customer entering a department store will either buy or not buy some merchandise. An experiment consists of following 4 customers and determining whether or not they purchase any merchandise. How many sample points exist in the above experiment? (Note that each customer is either a purchaser or non-purchaser.)
a. 2
b. 4
c. 12
d. 16

D

91. From nine cards numbered 1 through 9, two cards are drawn. Consider the selection and classification of the cards as odd or even as an experiment. How many sample points are there for this experiment?
a. 2
b. 3
c. 4
d. 9

C