Figure 2.

Redrawn from Fig. 5.3 of Armitage [20], with the kind permission of Blackwell Publishing. 2α = 0.05. β = 0.05. d = difference between means for each matched-pair. γ = cumulative sum of differences between means. σ = common standard deviation. N = number of matched pairs. _____ = restricted plan. - - - - - = RST plan.