# Statistics MCQs – Discrete Distributions Part 5

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81. Forty percent of the passengers who fly on a certain route do not check in any luggage. The planes on this route seat 15 passengers. For a full flight, what is the mean of the number of passengers who do not check in any luggage?

a. 6.00

b. 6.45

c. 7.20

d. 7.50

e. 4.50

Answer: A

82.43 % percent of the passengers who fly on a certain route do not check in any luggage. The planes on this route seat 15 passengers. For a full flight, what is the mean of the number of passengers who do not check in any luggage?

a. 6.00

b. 6.45

c. 7.20

d. 7.50

e. 4.50

Answer: B

83. Forty percent of the passengers who fly on a certain route do not check in any luggage. The planes on this route seat 18 passengers. For a full flight, what is the mean of the number of passengers who do not check in any luggage?

a. 6.00

b. 6.45

c. 7.20

d. 7.50

e. 4.50

Answer: C

84. Fifty percent of the passengers who fly on a certain route do not check in any luggage. The planes on this route seat 15 passengers. For a full flight, what is the mean of the number of passengers who do not check in any luggage?

a. 6.00

b. 6.45

c. 7.20

d. 7.50

e. 4.50

Answer: D

85.25 % percent of the passengers who fly on a certain route do not check in any luggage. The planes on this route seat 18 passengers. For a full flight, what is the mean of the number of passengers who do not check in any luggage?

a. 6.00

b. 6.45

c. 7.20

d. 7.50

e. 4.50

Answer: E

86. A recent survey in Cape Town revealed that 60 % of the vehicles traveling on highways, where speed limits are posted at 80 km per hour, were exceeding the limit. Suppose you randomly record the speeds of 10 vehicles traveling on the N1 where the speed limit is 80 km per hour. What is the mean or expected number of vehicles who will exceed the speed limit in this sample?

a. 10

b. 4

c. 6

d. 1

e. 8

Answer: C

87. Cape Town is estimated to have 21 % of homes whose owners subscribe to the satellite television service, DSTV. If a random sample of four homes is taken, what is the mean number of homes in this sample that subscribe to DSTV?

a. 0.84

b. 1.00

c. 2.00

d. 0.21

e. 1.68

Answer: A

88. An important part of the customer service responsibilities of a telephone company relates to the speed with which problems in residential service can be repaired. Suppose past data indicate that the probability is 0.5 that problems in residential service can be repaired on the same day. On a given day 5 problems were reported. What is the standard deviation of the random variable describing the number of same day repairs in this sample?

a. -0.500

b. 0.500

c. 1.500

d. 1.118

e. 1.250

Answer: D

89. Forty percent of the passengers who fly on a certain route do not check in any luggage. The planes on this route seat 15 passengers. For a full flight, what is the variance of the number of passengers who do not check in any luggage?

a. 3.60

b. 3.68

c. 4.32

d. 3.75

e. 3.38

Answer: A

90.43 % percent of the passengers who fly on a certain route do not check in any luggage. The planes on this route seat 15 passengers. For a full flight, what is the variance of the number of passengers who do not check in any luggage?

a. 3.60

b. 3.68

c. 4.32

d. 3.75

e. 3.38

Answer: B

91. Forty percent of the passengers who fly on a certain route do not check in any luggage. The planes on this route seat 18 passengers. For a full flight, what is the variance of the number of passengers who do not check in any luggage?

a. 3.60

b. 3.68

c. 4.32

d. 3.75

e. 3.38

Answer: C

92. Fifty percent of the passengers who fly on a certain route do not check in any luggage. The planes on this route seat 15 passengers. For a full flight, what is the variance of the number of passengers who do not check in any luggage?

a. 3.60

b. 3.68

c. 4.32

d. 3.75

e. 3.38

Answer: D

93.25 % percent of the passengers who fly on a certain route do not check in any luggage. The planes on this route seat 18 passengers. For a full flight, what is the variance of the number of passengers who do not check in any luggage?

a. 3.60

b. 3.68

c. 4.32

d. 3.75

e. 3.38

Answer: E

94. It is believed that 70 % of STA1000S students got A՚s for their final matric exams. What is the standard deviation of the number of students who got A՚s for matric, in samples of size 10?

a. 1.45

b. 2.10

c. 1.37

d. 1.88

e. 3.85

Answer: A

95. It is believed that 70 % of STA1000S students got A՚s for their final matric exams. What is the variance of the number of students who got A՚s for matric, in samples of size 10?

a. 1.45

b. 2.10

c. 1.37

d. 1.88

e. 3.85

Answer: B

96. It is believed that 75 % of STA1000S students got A՚s for their final matric exams. What is the standard deviation of the number of students who got A՚s for matric, in samples of size 10?

a. 1.45

b. 2.10

c. 1.37

d. 1.88

e. 3.85

Answer: C

97. It is believed that 75 % of STA1000S students got A՚s for their final matric exams. What is the variance of the number of students who got A՚s for matric, in samples of size 10?

a. 1.45

b. 2.10

c. 1.37

d. 1.88

e. 3.85

Answer: D

98. It is believed that 70 % of STA1000S students got A՚s for their final matric exams. What is the standard deviation of the number of students who got A՚s for matric, in samples of size 20?

a. 2.05

b. 4.20

c. 1.26

d. 1.60

e. 3.85

Answer: A

99. It is believed that 70 % of STA1000S students got A՚s for their final matric exams. What is the variance of the number of students who got A՚s for matric, in samples of size 20?

a. 2.05

b. 4.20

c. 1.26

d. 1.60

e. 3.85

Answer: B

100. It is believed that 80 % of STA1000S students got A՚s for their final matric exams. What is the standard deviation of the number of students who got A՚s for matric, in samples of size 10?

a. 2.05

b. 4.20

c. 1.26

d. 1.60

e. 3.85

Answer: C