31. Evidence for alternative Medical Therapies? A company called QT, Inc., sells “ionized” bracelets, called Q-Ray bracelets, that it claims help to ease pain through balancing the body's flow of “electromagnetic energy.” The Mayo Clinic decided to conduct a statistical experiment to determine whether the claims for the Q-Ray bracelets were justified.17 At the end of 4 weeks, of the 305 subjects who wore the “ionized” bracelet, 236 (77.4%) reported improvement in their maximum pain index (where the pain was the worst). Of the 305 subjects who wore the placebo bracelet (a bracelet identical in every respect to the “ionized” bracelet except that there was no active ingredient—presumably, here, “ionization”), 234 (76.7%) reported improvement in their maximum pain index. Using level of significance , test whether the population proportions reporting improvement differ between wearers of the ionized bracelet and wearers of the placebo bracelet.
10.3.31
. Reject if the . . . . Since the is not , we do not reject . There is insufficient evidence that the proportion of the people who wore the ionized bracelets who reported improvement in their maximum pain index is different from the proportion of the people who wore the placebo bracelets who reported improvement in their maximum pain index.