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Question 11A sample of 250 people resulted in a confidence interval estimate for the proportion of people who believe that the federal government's proposed tax increase is justified is between 0.14 and0.20. Based on this information, what was the confidence level used in this estimation?Correct!Approximately 79 percent95 percentApproximately 1.59Can't be determined without knowing σ.Question 12A survey of 499 women for the American Orthopedic Foot and Ankle Society revealed that 38% wear flats to work.Use this sample information to develop a 99% confidence interval for the population proportion of women who wear flats to work.
Question 13A public policy research group is conducting a study of health care plans and would like to estimate the average dollars contributed annually to health savings accounts by participating employees. A pilot study conducted a few months earlier indicated that the standard deviation ofannual contributions to such plans was $1,225. The research group wants the study's findings tobe within $100 of the true mean with a confidence level of 90%. What sample size is required?Question 14A production process that fills 12-ounce cereal boxes is known to have a population standard deviation of 0.009 ounce. If a consumer protection agency would like to estimate the mean fill, inounces, for 12-ounce cereal boxes with a confidence level of 92% and a margin of error of 0.001, what size sample must be used?Question 15According to USA Today,customers are not settling for automobiles straight off the production lines. As an example, those who purchase a $355,000 Rolls-Royce typically add $25,000 in accessories. One of the affordable automobiles to receive additions is BMW's Mini Cooper. A sample of 179 recent Mini purchasers yielded a sample mean of $5,000 above the $20,200 base sticker price. Suppose the cost of accessories purchased for all Mini Coopers has a standard deviation of $1,500.Calculate a 95% confidence interval for the average cost of accessories on Mini Coopers.Question 16
The file Danish Coffee contains a random sample of 144 Danish coffee drinkers and measures the annual coffee consumption in kilograms for each sampled coffee drinker. A marketing research firm wants to use this information to develop an advertising campaign to increase Danish coffee consumption.Based on the sample's results, what is the best point estimate of average annual coffeeconsumption for Danish coffee drinkers?