Unformatted text preview: 86. As the margin of error decreases, the width of the confidence interval _______________.
A. Stays the same
B. Decreases
C. Increases AACSB: Reflective Thinking
Bloom's: Comprehension
Difficulty: Medium
Topic: Confidence interval 87. If everything else is held constant, decreasing the margin of error, __________ the
required sample size.
A. Stays the same
B. Decreases
C. Increases AACSB: Reflective Thinking
Bloom's: Synthesis
Difficulty: Medium
Topic: Confidence interval 1684 Chapter 01  An Introduction to Business Statistics 88. A confidence interval for the population mean is an interval constructed around the
_____.
A. Sample mean
B. Population mean
C. Z test statistic
D. t test statistic AACSB: Reflective Thinking
Bloom's: Knowledge
Difficulty: Medium
Topic: Confidence interval for population mean 89. In determining the sample size to estimate a population proportion, as p approaches .5, the
calculated value of the sample size ______________.
A. Stays the same
B. Decreases
C. Increases AACSB: Reflective Thinking
Bloom's: Analysis
Difficulty: Medium
Topic: Sample size determination for population proportion 90. The tolerance interval of 95.44 percent is ________ a 95.44 percent confidence interval.
A. the same width as
B. narrower than
C. wider than AACSB: Reflective Thinking
Bloom's: Knowledge
Difficulty: Medium
Topic: Confidence interval 1685 Chapter 01  An Introduction to Business Statistics 91. A random sample of size 30 from a normal population yields
= 32.8 with a population
standard deviation of 4.51. Construct a 95 percent confidence interval for
.
A. [23.96 41.64]
B. [32.04 33.56]
C. [31.45 34.15]
D. [31.19 34.41] AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Confidence interval for population mean σ known 92. A sample set of weights in pounds are 1.01, .95, 1.03, 1.04, .97, .97, .99, 1.01, and 1.03.
Assume the population of weights are normally distributed. Find a 99 percent confidence
interval for the mean population weight.
A. [.965 1.035]
B. [.969 1.031]
C. [.973 1.027]
D. [.941 1.059] AACSB: Analytic
Bloom's: Application
Difficulty: Hard
Topic: Confidence interval for population mean σ unknown 1686 Chapter 01  An Introduction to Business Statistics 93. A sample of 8 items has an average fat content of 18.6 grams and a standard deviation of
2.4 grams. Assuming a normal distribution, construct a 99 percent confidence interval for .
A. [16.06 21.14]
B. [16.42 20.78]
C. [15.63 21.57]
D. [15.75 21.45] AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Confidence interval for population mean σ unknown 94. A sample of 12 items yields
= 48.5 grams and s = 1.5 grams. Assuming a normal
distribution, construct a 90 percent confidence interval for the population mean weight.
A. [47.722 49.278]
B. [47.788 49.212]
C. [45.806 51.194]
D. [47.865 49.135] AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Confidence interval for population mean σ unknown 1687 Chapter 01  An Introduction to Business Statistics 95. A sample of 100 items has a population standard deviation of 5.1 and a mean of 21.6.
Construct a 95 percent confidence interval for .
A. [11.60 31.60]
B. [21.16 22.04]
C. [20.60 22.60]
D. [20.76 22.43] AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Confidence interval for population mean σ known 96. In a survey of 1,000 people, 420 are opposed to the tax increase. Construct a 95 percent
confidence interval for the proportion of those people opposed to the tax increase.
A. [.394 .446]
B. [.389 .451]
C. [.380 .460]
D. [.399 .441] AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Confidence interval for population proportion 1688 Chapter 01  An Introduction to Business Statistics 97. Of a random sample of 600 trucks at a bridge, 114 had bad signal lights. Construct a 98
percent confidence interval for the percentage of trucks that had bad signal lights.
A. [.1754 .2046]
B. [.1740 .2060]
C. [.1572 .2228]
D. [.1527 .2273] AACSB: Analytic
Bloom's: Application
Difficulty: Hard
Topic: Confidence interval for population proportion 98. The success rate of a procedure is 37 per 120 cases in a sample. Find a 95 percent
confidence interval for the actual success proportion of the procedure.
A. [.2975 .4425]
B. [.2389 .3776]
C. [.2836 .4564]
D. [.2250 .3910] AACSB: Analytic
Bloom's: Application
Difficulty: Medium
Topic: Confidence interval for population proportion 1689 Chapter 01  An Introduction to Business Statistics 99. What sample size is needed to obtain a 90 percent confidence interval for the mean protein
content of meat if the estimate is to be within 2 pounds of the true mean value? Assume that
the variance is 49 pounds.
A. 34
B. 1625
C. 21
D. 987 AACSB: Analytic
Bloom's: Application
Difficulty: Hard
Topic: Sample size determination for population mean 100. What sample size is needed to obtain a 95 percent confidence interval for the proportion
of fat in meat that is within 3 percent of the true value?
A. 267
B. 106...
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 Winter '14

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