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Unformatted text preview: al production measures the weight of a cereal
box. The population standard deviation is known to be .06 ounces. In order to achieve a 97%
confidence with a margin of error of .02 ounces, how large a sample should be used?
A. 32
B. 43
C. 7
D. 664 AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Sample size determination for population mean 1709 Chapter 01  An Introduction to Business Statistics 140. The production manager for the XYZ manufacturing company is concerned that the
customer orders are being shipped late. He asked one of his planners to check the timeliness
of shipments. The planner randomly selected 1000 orders and found that 120 orders were
shipped late. Construct the 95% confidence interval for the proportion of orders shipped late.
A. [.0999 .1401]
B. [.1135 .1265]
C. [.0619 .1781]
D. [.1011 .1389] AACSB: Analytic
Bloom's: Application
Difficulty: Hard
Topic: Confidence interval for population proportion 141. Research has been conducted that studies the role that the age of workers has in
determining the hours per month spent on personal tasks. A sample of 1,686 adults were
observed for one month. The data are: Construct an 88% confidence interval for the mean hours spent on personal tasks for 1824
year olds.
A. [4.09 4.25]
B. [4.11 4.23]
C. [4.08 4.26]
D. [4.14 4.20]
E. [4.15 4.19] AACSB: Analytic
Bloom's: Application
Difficulty: Hard
Topic: Confidence interval for population mean σ unknown 1710 Chapter 01  An Introduction to Business Statistics 142. Research has been conducted that studies the role that the age of workers has in
determining the hours per month spent on personal tasks. A sample of 1,686 adults were
observed for one month. The data are: Construct a 93% confidence interval for the mean hours spent on personal tasks for 4564
year olds.
A. [4.26 4.36]
B. [4.25 4.37]
C. [4.27 4.35]
D. [4.28 4.34]
E. [2.83 5.79] AACSB: Analytic
Bloom's: Application
Difficulty: Hard
Topic: Confidence interval for population mean σ unknown 143. Unoccupied seats on flights cause airlines to lose revenue. Suppose a large airline wants
to estimate its average number of unoccupied seats per flight over the past year. 225 flight
records are randomly selected and the number of unoccupied seats is noted with a sample
mean of 11.6 seats and a standard deviation of 4.1 seats. Calculate a 95% confidence interval
for
, the mean number of unoccupied seats per flight during the past year.
A. [11.06 12.14]
B. [11.34 11.86]
C. [10.44 12.76]
D. [11.15 12.05]
E. [3.56 19.64] AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Confidence interval for population mean σ unknown 1711 Chapter 01  An Introduction to Business Statistics 144. Unoccupied seats on flights cause airlines to lose revenue. Suppose a large airline wants
to estimate its average number of unoccupied seats per flight over the past year. 225 flight
records are randomly selected and the number of unoccupied seats is noted with a sample
mean of 11.6 seats and a standard deviation of 4.1 seats. How many flights should we select if
we wish to estimate µ to within 5 seats and be 95% confident?
A. 44
B. 3
C. 2
D. 110
E. 6 AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Sample size determination for population mean Chapter 09
Hypothesis Testing
True / False Questions 1. The manager of the quality department for a tire manufacturing company wants to know
the average tensile strength of rubber used in making a certain brand of radial tire. The
population is normally distributed and the population standard deviation is known. She uses a
Z test to test the null hypothesis that the mean tensile strength is less than or equal to 800
pounds per square inch. The calculated Z test statistic is a positive value that leads to a pvalue of .067 for the test. If the significance level is .10, the null hypothesis would be
rejected.
True False 2. The manager of the quality department for a tire manufacturing company wants to know
the average tensile strength of rubber used in making a certain brand of radial tire. The
population is normally distributed and the population standard deviation is known. She uses a
Z test to test the null hypothesis that the mean tensile strength is 800 pounds per square inch.
The calculated Z test statistic is a positive value that leads to a pvalue of .045 for the test. If
the significance level (α) is .05, the null hypothesis would be rejected.
True False 1712 Chapter 01  An Introduction to Business Statistics 3. A Type I error is rejecting a true null hypothesis.
True False 4. The larger the pvalue, the more we doubt the null hypothesis.
True False 5. A Type II error is failing to reject a false null hypothesis.
True False 1713 Chapter 01  An Introduction to Business Statistics 6. You cannot make a Type II error when the null hypothesis is true.
True False 7. For a hypothesis test about a population proportion or mean, if the level of significance is
less than the pvalue, the null hypothesis is rejected.
True False 8. Alpha (α) is the probabi...
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 Winter '14

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