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NAME ________________________________________________________________ TAKE HOME EXAM 1. 2. 3. 4. 5. 6. When a 99% confidence interval is calculated instead of a 95% confidence interval with n being the same, the maximum error of estimate will be: (A) Smaller (B) Larger (C) The same (D) It cannot be determined 7. The best point estimate of the population mean is: (A) sample mean (B) sample median (C) sample mode 8. (D) sample midrange DO YOU DRINK THE CEREAL MILK? A USA TODAY poll asked a random sample of 1012 U.S. adults what they do with the milk in the bowl after they have eaten the cereal. Of the respondents, 67% said that they drink it. Suppose that 70% of U.S. adults actually drink the cereal milk. (a) Find the mean and standard deviation of the proportion of the sample (p-hat) that say they drink the cereal milk. (b) Show how you would check that you can use the normal approximation for the distribution of p-hat. (c) Find the probability of obtaining a sample of 1012 adults in which 67% or fewer say they drink the cereal milk. 9. What is the difference between a point estimate and an interval estimate of a parameter? Which is better? Why? 10. The growing seasons for a random sample of 35 U.S. cities were recorded, yielding a sample mean of 190.7 days and a sample standard deviation of 54.2 days. Estimate the true mean population of the growing season with 95% confidence. 11. Sherdale is interested in estimating the average monthly salary of sports reporters in a large city. He wants to be 90% confident that his estimate is correct. If the standard deviation is $1100, how large a sample is needed to get the desired information and to be accurate within $150. 12. 13.