1. Lipitor is a drug used to control cholesterol. In clinical trials of Lipitor, 94 subjects were treated with Lipitor and 270 subjects were given placebo. Among those treated with Lipitor, 7 developed infections. Among those given a placebo, 27 developed infections. Use a 0.05 significance level to test the claim that the rate of infection was the same for those treated with Lipitor and those given a placebo.
2. A study was conducted after 55 years to find radiation dose response relationships for thyroid nodules and autoimmune thyroid disease in Hiroshima and Nagasaki atomic bomb survivors after radiation exposure. Among 2739 female atom bomb survivors, 1397 developed thyroid diseases. Among 1352 male atom bomb survivors, 436 developed thyroid diseases. Use a 0.01 significance level to test the claim that the female survivors and male survivors have different rates of thyroid diseases.