A two proportion z-test is used to test for a difference between two population proportions. The test statistic is calculated as:
z = (p1-p2) / √(p(1-p)(1/n1+1/n2)
where:
- p = total pooled proportion
- p1 = sample 1 proportion
- p2 = sample 2 proportion
- n1 = sample 1 size
- n2 = sample 2 size
To perform a two proportion z-test, simply fill in the information below and then click the “Calculate” button.
z-statistic: 0.31917
p-value (one-tailed): 0.37480
p-value (two-tailed): 0.74960