p-values in One Tail Test of a Standard Normal Curve *

 

z = [ Pt -Pc ] / [ pq (1/Nt + 1/Nc) ]^1/2, where:

Pt = Xt/Nt = risk to test group

Pc = Xc/Nc = risk to control group

p = [Xt + Xc] / [Nt + Nc ]

q = 1-p

Z	p-value
0.0	.500
0.5	.309
1.0	.159
1.5	.067
1.6	.055
1.7	.045
1.8	.036
1.9	.029
2.0	.023
2.1	.018
2.2	.014
2.3	.011
2.4	.008
2.5	.006
3.0	.001

* Numbers in bold represent the most sensitive area of the curve.  If cases are in between the numbers listed, a linear interpolation can estimate the value. This table is for demonstration purposes only, and the analyst is encouraged to used more accurate tables available on varius computer programs.