Clinical Test of Lipitor The cholesterol-reducing drug Lipitor consists of atorvastatin calcium, and results summarizing headaches as an adverse reaction in clinical tests are given in the table (based on data from Parke-Davis). Using a 0.05 significance level, test the claim that getting a headache is independent of the amount of atorvastatin used as a treatment. (Hint: Because not all of the expected values are 5 or greater, combine the results for the treatments consisting of 20 mg of atorvastatin and 40 mg of atorvastatin.)