Compare two sample proportions using the 2-sample z-test. P-values can be calculated for one or two-tailed comparisons and are compared results to a specified significance level.

Inputs are:

sample proportions for each sample;

sample sizes for each sample;

specified significance level; and

whether test is one-tailed or two-tailed.

Outputs include:

difference in sample proportions;

Asymptotic (normal approximation) confidence limits (based on specified significance level) for the proportions and their difference;

z and P values for the difference in proportions and their interpretation;

whether or not z * p values are > 5 (to ensure test validity); and