P value from Z score Calculator

Z score:

P value from Z score Examples

Z score is based on normal distribution.

For a one-sided Z-test, if |z|=1.282 or more, p<0.10; if |z|=1.645 or more, p<0.05; if |z|=2.327 or more, p<0.01; if |z|=3.091 or more, p<0.001.

For a two-sided Z-test, if |z|=1.645 or more, p<0.10; if |z|=1.960 or more, p<0.05; if |z|=2.576 or more, p<0.01; if |z|=3.291 or more, p<0.001.

In the famous six-sigma test, try z=6, you get P(z>6)=9.8659e-10. If there is a 1.5 sigma shift with z=4.5, you get P(z>4.5)=0.0000034, or about 3.4 per million.