µ1-µ 2 = 4.9 - 3.7 mm = 1.2 (µ1-µ 2)2 = 1.44 (COCP equivalence) µ1-µ 2 = 1.8 - 1.2 mm = 0.6 (µ1-µ 2)2 = 0.36 (COCP superiority) SD = б=0.75 б2 = 0.5625 2 б2 = 1.125 α = 0.05 Zα = 1.96 (2-sided test) β = 0.20 1- β = 0.80 Z β = 0.84 (1-sided) (Zα +Zβ)2= 7.84 β =0.15 1- β = 0.85 Z β = 1.03 (1-sided) (Zα +Zβ) 2= 8.94 β = 0.10 1- β = 0.90 Z β = 1.28 (1-sided) (Zα +Zβ) 2= 10.498 β = 0.05 1- β = 0.95 Z β = 1.645 (1-sided) (Zα +Zβ) 2 =12.996