The Proportion Test computes a test statistic to determine if a specific category in a sample has a different proportion than the expected proportion, p ₀ . The node calculates the sample proportion of the category p̂. With the given null-hypothesized proportion p ₀ , a z-Score is calculated via (p̂ - p ₀ )/ se , where se is the standard error. If the corresponding p -Value is below the given significance level α, the null hypothesis can be rejected. Missing values will be ignored. See Wikipedia on test statistic , "One-proportion z-test" for further information.