Hypothesis Test
z- and t-tests with p-value and rejection region
About this calculator
The Hypothesis Test Calculator runs a one-sample z-test or t-test for a mean, or a z-test for a proportion, with a two-sided or one-tailed alternative. It reports the test statistic, the exact p-value, the critical value and rejection region, the standard error, and the reject / fail-to-reject decision at your chosen significance level α. A shaded density curve shows where the statistic falls relative to the rejection region, making the decision easy to see. Useful for statistics coursework, A/B testing, and quality control.