[Comparison of k therapies after determination of success and failure]

To compare k therapeutic methods, N patients are suggested to be assigned to k therapies at random. The effect of each therapy is rated to be present or absent. The resulting k x 2 contingency table is evaluated according to one of the following questions: 1) Do the k therapies differ in their effects? 2) Is a given therapy more effective than the k-1 remaining therapies? 3) Is a given therapy more effective than a competitive therapy? The methods are exemplified by a numerical example from treatments of schizophrenics.