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Unformatted text preview: al random variable with mean 50
feet and standard deviation 5 feet, what is the probability he throws it:
Between 50 feet and 60 feet?
A. .9972
B. .5000
C. .9544
D. .4772 1449 Chapter 01  An Introduction to Business Statistics 65. If the scores on an aptitude test are normally distributed with mean 500 and standard
deviation 100, what proportion of the test scores are less than 585?
A. .1977
B. .8500
C. .1500
D. .8023 66. If x is a binomial random variable where n = 100 and p = .1, find the probability that x is
less than or equal to 10 using the normal approximation to the binomial.
A. .9544
B. .0446
C. .5675
D. .4325 67. What is the probability that a random variable having a standard normal distribution is
between .87 and 1.28?
A. .0919
B. .4100
C. .6517
D. .3483 68. The probability that an appliance is in repair is .5. If an apartment complex has 100 such
appliances, what is the probability that at least 60 will be in repair? Use the normal
approximation to the binomial.
A. .5000
B. .0287
C. .6000
D. .9713 1450 Chapter 01  An Introduction to Business Statistics 69. The flying time of a drone airplane has a normal distribution with mean 4.76 hours and
standard deviation of .04 hours. What is the probability that the drone will fly:
Less than 4.66 hours?
A. .0062
B. .5062
C. .0062
D. .9938 70. The flying time of a drone airplane has a normal distribution with mean 4.76 hours and
standard deviation of .04 hours. What is the probability that the drone will fly:
More than 4.80 hours?
A. .1587
B. .8413
C. .6587
D. /3413 71. The flying time of a drone airplane has a normal distribution with mean 4.76 hours and
standard deviation of .04 hours. What is the probability that the drone will fly:
Between 4.70 and 4.82 hours?
A. .1336
B. .8664
C. .9332
D. .4332 72. What is the probability that a standard normal random variable will be between 2 and 2?
A. .4772
B. .0228
C. .9772
D. .9544 1451 Chapter 01  An Introduction to Business Statistics 73. What is the probability that a standard normal random variable will be between .3 and
3.2?
A. .6179
B. .3808
C. .6192
D. .9987 74. The life of a light bulb is exponentially distributed with a mean of 1,000 hours. What is
the probability that the bulb will last:
More than 1,200 hours?
A. .3012
B. .3679
C. .4345
D. .6988 75. The life of a light bulb is exponentially distributed with a mean of 1,000 hours. What is
the probability that the bulb will last:
Less than 800 hours?
A. .6321
B. .5507
C. .7135
D. .4493 76. The lifetime of a stereo component is exponentially distributed with mean 1,000 days.
What is the probability that the lifetime:
Exceeds 1,000 days?
A. .6321
B. .5000
C. .3679
D. 1.000 1452 Chapter 01  An Introduction to Business Statistics 77. The lifetime of a stereo component is exponentially distributed with mean 1,000 days.
What is the probability that the lifetime:
Is greater than or equal to 700 days?
A. .7603
B. .5034
C. .2397
D. .4966 78. The time between breakdowns of an alarm system is exponentially distributed with mean
10 days. What is the probability that there are no breakdowns on a given day?
A. .9048
B. .3679
C. .0952
D. 0.000 79. An aptitude test has a mean score of 80 and a standard deviation of 5. The population of
scores is normally distributed. What proportion of tests has scores over 90?
A. .9772
B. .0228
C. .9544
D. .0456 80. An aptitude test has a mean score of 80 and a standard deviation of 5. The population of
scores is normally distributed. What raw score corresponds to the 70th percentile?
A. 77.4
B. 83.5
C. 82.6
D. 76.5 1453 Chapter 01  An Introduction to Business Statistics 81. Suppose the daily change in price of a stock is normally distributed with mean = .20 and
standard deviation = .30. What price change is associated with the 25th percentile?
A. .1925
B. .2075
C. .401
D. .001 82. If the mileage per gallon for a car is normally distributed, 32 mpg has a zscore of 1.2, and
24 mpg has a zscore of .4, what is the mean mpg of the distribution?
A. 28
B. 26
C. 30
D. 38 83. Consider a normal population with a mean of 10 and a standard deviation 2.
Find P(X > 13).
A. .0668
B. .9544
C. .0456
D. .9332 84. Consider a normal population with a mean of 10 and a standard deviation 2.
Find P(X < 12).
A. .1587
B. .9544
C. .0456
D. .8413 85. Consider a normal population with a mean of 10 and a standard deviation 2.
Find P(X = 10).
A. 1.00
B. 0.99
C. 0.00
D. 0.01 1454 Chapter 01  An Introduction to Business Statistics 86. Consider a normal population with a mean of 10 and a variance of 4. Find P(X < 6).
A. .0228
B. .1587
C. .8413
D. .9772 87. Consider a normal population with a mean of 10 and a variance of 4.Find P(X > 7).
A. .0668
B. .9332
C. .8413
D. .1587 88. Consider a normal population with a mean of 10 and a variance of 4.Find P(X > 18).
A. 1.00
B. 0.00
C. .9772
D. .0228 89. Consider a normal population with a mean of 10 and a variance of 4.Find P(X ≥ 10).
A. 1.00
B. 0.00
C. 0.50
D. 0.50 90. The population of le...
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This document was uploaded on 01/20/2014.
 Winter '14

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