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STATS Ten Questions Set




Question;Question 1 of 10A sample of 25 different payroll departments found that the employees worked an average of 310.3 days ayear with a standard deviation of 23.8 days. What is the 90% confidence interval for the average daysworked by employees in all payroll departments?A. 301.0 << 319.6B. 298.0 << 322.6C. 302.2 << 318.4D. 314.1 << 316.8Question 2 of 10A previous study of nickels showed that the standard deviation of the weight of nickels is 150 milligrams.How many nickels does a coin counter manufacturer need to weigh so that she can be 98% confident that hersample mean is within 25 milligrams of the true average weight of a nickel?A. 36B. 196C. 239D. 139Question 3 of 10A food snack manufacturer samples 15 bags of pretzels off the assembly line and weighed their contents. Ifthe sample mean is 10.0 and the sample standard deviation is 0.15, find the 95% confidence interval estimatefor the true mean.A. (9.96, 10.04)B. (9.68, 10.32)C. (9.97, 10.80)D. (9.92, 10.08)Question 4 of 10A recent study of 750 Internet users in Europe found that 35% of Internet users were women. What is the95% confidence interval estimate for the true proportion of women in Europe who use the Internet?A. 0.321 < p < 0.379B. 0.316 < p < 0.384C. 0.309 < p < 0.391D. 0.305 < p < 0.395Question 5 of 10A researcher wishes to know, with 98% confidence, the percentage of women who wear shoes that are toosmall for their feet. A previous study conducted by the Academy of Orthopedic Surgeons found that 80% ofwomen wear shoes that are too small for their feet. If the researcher wants her estimate to be within 3% ofthe true proportion, how large a sample is necessary?A. 966B. 683C. 183D. 484Question 6 of 10A sample of 23 European countries found that the variance of life expectancy was 7.3 years. What is the 95%confidence interval estimate for the variance of life expectancy in Europe?A. 27.2 << 118.3B. 5.6 << 10.3C. 4.4 << 14.6D. 28.9 << 115.0Question 7 of 10Find the 95% confidence interval for the standard deviation of the lengths of pipes if a sample of 26 pipes hasa standard deviation of 10 inches.A. 14.0


Paper#61575 | Written in 18-Jul-2015

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