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random sample of 300 Ivey University freshmen.
A. [236.45 273.55]
B. [26.45 63.55]
C. [110.25 369.75]
D. [38.82 51.18] 1360 Chapter 01  An Introduction to Business Statistics 49. The variable "employment status" which can take on one of two values: 1 for "employed"
and 0 for "unemployed" is an example of a _____________ random variable.
A. Poisson
B. Discrete
C. Hypergeometric
D. Continuous 50. If x is a binomial random variable, then the standard deviation of x is given by
A. np
B. (npq)2
C. √npq
D. npq 51. A random variable that is defined to be the total number of successes in n trials is a _____
random variable.
A. Binomial
B. Poisson
C. Hypergeometric
D. Continuous 52. A discrete variable that can often be used to describe the number of occurrences of an
event over a specified interval of time or space is a _____ random variable.
A. Poisson
B. Discrete
C. Hypergeometric
D. Continuous 53. The requirement that the probability of success remains constant from trial to trial is a
property of the _______________ distribution.
A. Binomial
B. Poisson
C. Hypergeometric
D. Continuous 1361 Chapter 01  An Introduction to Business Statistics 54. The distribution whose mean is equal to its variance is the _________ distribution.
A. Binomial
B. Poisson
C. Hypergeometric
D. Continuous 55. For a random variable X, the mean value of the squared deviations of its values from their
expected value is called its
A. Standard Deviation
B. Mean
C. Probability
D. Variance 56. The J.O. Supplies Company buys calculators from a Korean supplier. The probability of a
defective calculator is 10%.
If 3 calculators are selected at random, what is the probability that one of the calculators will
be defective?
A. .0702
B. .0010
C. .2430
D. .7290 57. The J.O. Supplies Company buys calculators from a Korean supplier. The probability of a
defective calculator is 10%.
If 10 calculators are selected at random, what is the probability that 3 or more of the
calculators will be defective?
A. .0702
B. .2639
C. .0016
D. 0 1362 Chapter 01  An Introduction to Business Statistics 58. The J.O. Supplies Company buys calculators from a Korean supplier. The probability of a
defective calculator is 10%.
If 100 calculators are selected at random, what is the expected number of defectives?
A. 9
B. 90
C. 10
D. 95 59. The J.O. Supplies Company buys calculators from a Korean supplier. The probability of a
defective calculator is 10%.
If 100 calculators are selected at random, what is the standard deviation of the number of
defectives?
A. 9.00
B. 3.17
C. 9.49
D. 3.00 60. Historical data shows that the average number of patient arrivals at the intensive care unit
of General Hospital is 3 patients every 2 hours. Assume that the patient arrivals are distributed
according to Poisson distribution.
Determine the probability of 6 patients arriving in a fivehour period.
A. .136
B. .109
C. .246
D. .001 61. Historical data shows that the average number of patient arrivals at the intensive care unit
of General Hospital is 3 patients every 2 hours. Assume that the patient arrivals are distributed
according to Poisson distribution.
Determine the probability of at least 4 but no more than 8 patients arriving in a threehour
period.
A. .3813
B. .5711
C. .4276
D. .7861
E. .6174 1363 Chapter 01  An Introduction to Business Statistics 62. If the probability distribution of X is: What is the expected value of X?
A. 1.0
B. 5.0
C. 2.25
D. 2.24 63. If the probability distribution of X is: What is the variance of X?
A. 1.0
B. 5.0
C. 2.25
D. 2.24 64. Assume the number of trucks passing an intersection has a Poisson distribution with mean
of 5 trucks per minute. What is the probability of 0 or 1 trucks in one minute?
A. .0404
B. .0337
C. .0842
D. .0067 1364 Chapter 01  An Introduction to Business Statistics 65. A vaccine is 95 percent effective. What is the probability that it is not effective for:
One and only one individual out of 20 individuals?
A. .0179
B. .3585
C. .0189
D. .3774 66. A vaccine is 95 percent effective. What is the probability that it is not effective for:
More than one out of 20 individuals?
A. .7359
B. .3585
C. .2641
D. .3774 67. If the probability of a success on a single trial is .2, what is the probability of obtaining 3
successes in 10 trials if the number of successes is binomial?
A. .0031
B. .5033
C. .1074
D. .2013 68. The number of calls coming into a PBX follows a Poisson process with a mean of 120
calls per hour. What is the probability of no calls in a oneminute interval?
A. 0
B. .1353
C. .4060
D. .3679 69. If x is a Poisson random variable with a mean of 10, what is the probability that x is
greater than 6?
A. .9329
B. .7797
C. .8698
D. .0002 1365 Chapter 01  An Introduction to Business Statistics 70. Three candidates run for different offices in different counties. Each has a one in three
chance of being elected in his/her county. What is the probability that at least one of them will
be elected?
A. .2963
B. .7037
C. .33
D. .667 71. A tes...
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