Table 2. Significance level for one-sided test, power and corresponding Z values.

Alpha or Beta	Zα or Zβ
0.005	2.58	Significance level = 0.01 for 2 sided test
0.025	1.96	Significance level = 0.05 for 2 sided test
0.05	1.645	Significance level = 0.1 for 2 sided test
0.1	1.28	Power (1 - β) = 0.9
0.2	0.84	Power (1 - β) = 0.8