Question: Suppose that you are interested in determining whether the advice given by a physician during a routine physical examination is effective in encouraging patients to stop smoking. In a study of current smokers, one group of patients was given a brief talk about the hazards of smoking and was encouraged to quit. A second group received no talk related to smoking. All patients were given a follow-up exam. In the sample of 120 patients who had received the talk, 18 reported that they had quit smoking. In the sample of 86 patients that hadn’t received a talk 5 had ceased smoking.

a. Conduct a test to determine whether a difference exists in the proportion of smokers that had quit smoking.

b. Use a different method than you used in a. to retest the same hypothesis that you tested in a. You have 4 methods (CI, hypothesis test using test statistic, hypothesis test using p-value, and chi-square test).