Statistical power of various levels of replication of the control group as the variance increases.

The difference between the treatment and control groups is fixed at 2. Three strategies for selecting the size of the control group were considered: (i) Optimal, according to the theoretical derivation, (ii) Equal to the treatment groups and (iii) Less than, where the control group replication is less than the treatment groups.†: for control group replication strategy (i) is approximately , (ii) and (iii) ,specifically: a: , b: , c: and d: .Statistical power of various levels of replication of the control group as the variance increases.