Cochran's Q Statistic:

Cochran's Q statistic is computed from replicated measurements data with binary responses. This statistic tests a difference in effects among 2 or more treatments applied to the same set of experimental units.

Consider the results of a study of M treatments applied to N experimental units (e.g patients or laboratory animals). The outcomes of individual measurements for the (i)th treatment of the (j)th unit are binary variables {V_ij;   i=1,...,M;   j=1,...,N} taking on two values "0" or "1" (e.g. "No effect" or "Effect is found").

The Cochran Q statistic is computed by the formula