Unformatted text preview: 120. Suppose that the waiting time for a license plate renewal at a local office of a state motor
vehicle department has been found to be normally distributed with a mean of 30 minutes and
a standard deviation of 8 minutes. What is the probability that a randomly selected individual
will have a waiting time no more than 22 minutes?
A. .1587
B. .9977
C. .8413
D. .0023 1463 Chapter 01  An Introduction to Business Statistics 121. Suppose that the waiting time for a license plate renewal at a local office of a state motor
vehicle department has been found to be normally distributed with a mean of 30 minutes and
a standard deviation of 8 minutes. Suppose that in an effort to provide better service to the
public, the director of the local office is permitted to provide discounts to those individuals
whose waiting time exceeds a predetermined time. The director decides that 15% of the
customers should receive this discount. What are the numbers of minutes they need to wait to
receive the discount?
A. 34.48
B. 21.68
C. 38.32
D. 25.52 122. Suppose that the waiting time for a license plate renewal at a local office of a state motor
vehicle department has been found to be normally distributed with a mean of 30 minutes and
a standard deviation of 8 minutes. Complete the following statement: Only 20% of the
individuals wait less than _____ minutes.
A. 36.72
B. 23.28
C. 34.63
D. 25.37 123. A set of final examination grades in a calculus course was found to be normally
distributed with a mean of 69 and a standard deviation of 9.
What is the probability of getting a grade of 91 or less on this exam?
A. 1.00
B. 0.50
C. 0.0073
D. .9927 124. A set of final examination grades in a calculus course was found to be normally
distributed with a mean of 69 and a standard deviation of 9.
What percentage of students scored between 65 and 89?
A. .6568
B. 1.000
C. .9868
D. .3300 1464 Chapter 01  An Introduction to Business Statistics 125. A set of final examination grades in a calculus course was found to be normally
distributed with a mean of 69 and a standard deviation of 9.
What percentage of students scored between 81 and 89?
A. .0668
B. .0132
C. .0536
D. .0529 126. A set of final examination grades in a calculus course was found to be normally
distributed with a mean of 69 and a standard deviation of 9.
Only 5% of the students taking the test scored higher than what grade?
A. 70.04
B. 67.96
C. 55.48
D. 82.52 127. A manufacturer of personal computers sets tests competing brands and finds that the
amounts of energy they require are normally distributed with a mean of 285 kwh and a
standard deviation of 9.1 kwh.
If the lowest 25% and the highest 30% are not included in a second round of tests, what are
the upper and lower limits for the energy amounts of the remaining sets?
A. [269.76 300.24]
B. [269.76 289.78]
C. [280.22 289.78]
D. [280.22 300.24] 128. While conducting experiments, a marine biologist selects water depths from a uniformly
distributed collection that vary between 2.00 m and 7.00 m. What is the probability that a
randomly selected depth is less than 3.60 m?
A. .72
B. .80
C. .46
D. .32 1465 Chapter 01  An Introduction to Business Statistics 129. While conducting experiments, a marine biologist selects water depths from a uniformly
distributed collection that vary between 2.00 m and 7.00 m. What is the probability that a
randomly selected depth is between 2.25 m and 5.00 m?
A. .79
B. .45
C. .55
D. .50 130. While conducting experiments, a marine biologist selects water depths from a uniformly
distributed collection that vary between 2.00 m and 7.00 m. What is the expected value of the
water depth?
A. 1.4
B. 2.6
C. 2.5
D. 4.5 131. While conducting experiments, a marine biologist selects water depths from a uniformly
distributed collection that vary between 2.00 m and 7.00 m. What is the standard deviation of
the water depth?
A. 1.4
B. 2.6
C. 2.5
D. 4.5 132. While conducting experiments, a marine biologist selects water depths from a uniformly
distributed collection that vary between 2.00 m and 7.00 m. What is the probability that a
randomly selected depth is within 1 standard deviation of the mean?
A. 0.320
B. 0.576
C. 0.600
D. 1.000 1466 Chapter 01  An Introduction to Business Statistics 133. An apple juice producer buys all his apples from a conglomerate of apple growers in one
northwest state. The amount of juice squeezed from each of these apples is approximately
normally distributed with a mean of 2.25 ounces and a standard deviation of 0.15 ounce.
What is the probability that a randomly selected apple will contain between 2.00 and 3.00
ounces?
A. .0475
B. .4525
C. .9525
D. .9554 134. An apple juice producer buys all his apples from a conglomerate of apple growers in one
northwest state. The amount of juice squeezed from each of these apples is approximately
normally distributed with a mean of 2.25 ounces and a standard deviation of 0.15 ounce.
What is the probability that a randomly selected apple will contain betwee...
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