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Construct a 95 confidence interval for the proportion

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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 1-684 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 1-685 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 1-686 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 1-687 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 1-688 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 1-689 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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