Statistics Confidence Intervals and Hypothesis Testing, Assignments of Statistics

Download Statistics Confidence Intervals and Hypothesis Testing and more Assignments Statistics in PDF only on Docsity! Assignment 9 Due date: 11/14/08 1. Suppose that a random sample of 50 bottles of a particular brand of cough medicine is selected and the alcohol content of each bottle is determined. Let μ denote the true average alcohol content for the population of all bottles of the brand under study. If the sample of 50 results in a 95% confidence interval for μ of (7:8; 9:4), which of the following statements is correct? A. There is a 95% chance that the true mean alcohol content, μ, of this brand falls between 7.8 and 9.4. B. The estimate, , is within 95% of the true mean, μ. C. If the process of selecting a sample of size 50 and then computing the corresponding 95% confidence interval is repeated many times, approximately 95% of the resulting intervals will include μ.. D. If the process of selecting a sample of size 50 and then computing the corresponding 95% confidence interval is repeated many times, approximately 95% of the resulting intervals will fall within (7:8; 9:4). . 2. Which of the following does NOT affect the width of a confidence interval for the mean of a normal population when σ is known? A. the population standard deviation B. the sample standard deviation C. the sample size D. the confidence level 3. Suppose a 90% confidence interval for the true proportion of A&M students who watch Walker: Texas Ranger is (0.22, 0.53), and a 90% confidence interval for the true proportion of t.u. students who watch is (0.29, 0.42). From this we can conclude A. more Aggies watch than t.u. students. B. less Aggies watch than t.u. students. C. it's plausible that the same proportion from either school watch. D. we have more confidence that the A&M interval contains the true proportion since it is wider than the other. Text-book Problem 6.19, 6.20, 6.32, 6.34