11.1 It is the responsibility of the federal government to judge the safety and effectiveness of new drugs. There are two possible decisions: approve the drug or disapprove the drug.

11.4 You are faced with two investments. One is very risky, but the potential returns are high. The other is safe, but the potential is quite limited. Pick one.

11.6 Several years ago in a high-profile case, a defendant was acquitted in a double-murder trial but was subsequently found responsible for the deaths in a civil trial. (Guess the name of the defendantthe answer is in Appendix C.) In a civil trial the plaintiff (the victims relatives) are required only to show that the preponderance of evidence points to the guilt of the defendant. Aside from the other issues in the cases, discuss why these results are logical.

11.8 H0: = 50 H1: > 50 = 5, n = 9, x = 51, = .03 11.9 H0: = 15 H1: < 15 = 2, n = 25, x = 14.3, = .10 11.10 H0: = 100 H1: 100 = 10, n = 100, x = 100, = .05

11.28 Xr11-28 A business student claims that, on average, an MBA student is required to prepare more than five cases per week. To examine the claim, a statistics professor asks a random sample of 10 MBA students to report the number of cases they prepare weekly. The results are exhibited here. Can the professor conclude at the 5% significance level that the claim is true, assuming that the number of cases is normally distributed with a standard deviation of 1.5? 2 7 4 8 9 5 11 3 7 4

11.33 Xr11-33 A machine that produces ball bearings is set so that the average diameter is .50 inch. A sample of 10 ball bearings was measured, with the results shown here. Assuming that the standard deviation is .05 inch, can we conclude at the 5% significance level that the mean diameter is not .50 inch? .48 .50 .49 .52 .53 .48 .49 .47 .46 .51

Developing an Understanding of Statistical Concepts 11.48 Calculate the probability of a Type II error for the following test of hypothesis, given that = 203. H0: = 200 H1: 200 = .05, = 10, n = 100

11.49 Find the probability of a Type II error for the following test of hypothesis, given that = 1,050. H0: = 1,000 H1: > 1,000 = .01, = 50, n = 25

11.66 The feasibility of constructing a profitable electricityproducing windmill depends on the mean velocity of the wind. For a certain type of windmill, the mean would have to exceed 20 miles per hour to warrant its construction. The determination of a sites feasibility is a two-stage process. In the first stage, readings of the wind velocity are taken and the mean is calculated. The test is designed to answer the question, Is the site feasible? In other words, is there sufficient evidence to conclude that the mean wind velocity exceeds 20 mph? If there is enough evidence, further testing is conducted. If there is not enough evidence, the site is removed from consideration. Discuss the consequences and potential costs of Type I and Type II errors.