4. To give a 75% confidence interval for a population mean , you would use the critical value Z* = Za? 200 2 (A. Z* = 1.96 8. Z 1.28 = A. The researcher increases the sample size. B. The researcher raises the confidence level. ESOS 16T-80 5. A researcher is planning to construct a one-sample z-confidence interval for a population mean . Select the statements that would lead to a larger margin of error, assuming the other factors remain the same. ex A. 2.576 B. 2.336 C. The researcher lowers the confidence level. D. The population standard deviation turns out to be lower than expected. k. z* = 1.15 D. Z* = 0.67 6. A sample of n=25 diners at a local restaurant had a mean lunch bill of $16. Assume that we know that the distribution of all lunch bills at the diner is Normal with a standard deviation of a = $5. The margin of error for a 99% confidence interval is given by: A. 22 B. 683 A. Ho: = 78 vs. H: = 88 B. Ho: = 88 vs. H1: < 88 7. Suppose we want a 90% confidence interval for the average