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Unformatted text preview: ic: Confidence interval for population proportion 74. At a sobriety checkpoint the sheriff's department screened 676 drivers and 6 were arrested for DWI. Find the 92% confidence interval for the true proportion of drivers who were DWI that evening. A. [0.000 0.027] B. [0.003 0.015] C. [0.902 0.938] D. [0.000 0.076] E. [0.006 0.030] AACSB: Analytic Bloom's: Application Difficulty: Hard Topic: Confidence interval for population proportion 1-679 Chapter 01 - An Introduction to Business Statistics 75. The Ohio Department of Agriculture tested 203 fuel samples across the state in 1999 for accuracy of the reported octane level. For premium grade, 14 out of 105 samples failed (they didn't meet ASTM specification and the FTC Octane posting rule). Find a 99% confidence interval for the true population proportion of premium grade fuel-quality failures. A. [.045 .221] B. [.068 .198] C. [.023 .115] D. [.047 .219] E. [.100 .276] AACSB: Analytic Bloom's: Application Difficulty: Medium Topic: Confidence interval for population proportion 76. The Ohio Department of Agriculture tested 203 fuel samples across the state in 1999 for accuracy of the reported octane level. For premium grade, 14 out of 105 samples failed (they didn't meet ASTM specification and the FTC Octane posting rule). How many samples would be needed to create a 99% confidence interval that is within 0.02 of the true proportion of premium grade fuel-quality failures? A. 4148 B. 2838 C. 1913 D. 744 E. 54 AACSB: Analytic Bloom's: Application Difficulty: Hard Topic: Sample size determination for population proportion 1-680 Chapter 01 - An Introduction to Business Statistics 77. To investigate the rate at which employees with cancer are fired or laid off, a telephone survey was taken of 100 cancer survivors who worked while undergoing treatment. Seven (7) were either fired or laid off due to their illness. Construct a 90% confidence interval for the true percentage of all cancer patients who are fired or laid off due to their illness. A. [0.0000 0.2034] B. [0.0371 0.1029] C. [0.0039 0.1361] D. [0.0278 0.1122] E. [0.0078 0.1400] AACSB: Analytic Bloom's: Application Difficulty: Hard Topic: Confidence interval for population proportion 78. In 1995, 13,000 WWW users were surveyed and asked about their willingness to pay fees for access to websites. Of these, 2,938 were definitely not willing to pay such fees. Construct a 95% confidence interval for the proportion definitely unwilling to pay fees. A. [0.286 0.302] B. [0.219 0.233] C. [0.220 0.232] D. [0.212 0.241] E. [0.214 0.245] AACSB: Analytic Bloom's: Application Difficulty: Medium Topic: Confidence interval for population proportion 1-681 Chapter 01 - An Introduction to Business Statistics 79. In 1995, 13,000 WWW users were surveyed and asked about their willingness to pay fees for access to websites. Of these, 2,938 were definitely not willing to pay such fees. How large a sample is necessary to estimate the proportion of interest to within 2% in a 95% confidence interval? A. 18 B. 307 C. 1717 D. 2000 E. 2965 AACSB: Analytic Bloom's: Application Difficulty: Medium Topic: Sample size determination for population proportion 80. In the construction of a confidence interval, as the confidence level required in estimating the mean increases, 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 for population mean 81. As the sample size n increases, 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 1-682 Chapter 01 - An Introduction to Business Statistics 82. When establishing the confidence interval for the average weight of a cereal box, assume that the population standard deviation is known to be 2 ounces, and based on a sample the average weight of a sample of 20 boxes is 16 ounces. The appropriate test statistics to use is ________. A. t B. Z C. χ D. p AACSB: Reflective Thinking Bloom's: Knowledge Difficulty: Medium Topic: Confidence interval for population mean σ known 83. As the significance level, α increases, 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 84. As the standard deviation, (σ) 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 for population mean σ known 1-683 Chapter 01 - An Introduction to Business Statistics 85. As the stated confidence level 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...
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