Stanley and Walton (1961) ran a controlled clinical trial to investigate the effect of t...

Stanley and Walton (1961) ran a controlled clinical trial to investigate the effect of the drug stelazine on chronic schizophrenics. The trials were conducted on chronic schizophrenics in two closed wards. In each of the wards, the patients were divided into two groups matched for age, length of time in the hospital, and score on a behavior rating sheet. One member of each pair was given stelazine, and the other a placebo. Only the hospital pharmacist knew which member of each pair received the actual drug. The following table gives the behavioral rating scores for the patients at the beginning of the trial and after 3 mo. High scores are good.

a. For each of the wards, test whether stelazine is associated with improvement in the patients’ scores.

b. Test if there is any difference in improvement between the wards. [These data are also presented in Lehmann (1975), who discusses methods of combining the data from the wards.]