P-Value & Critical Value Calculator

Understanding P-Values and Critical Values

The p-value is the probability of observing a test statistic as extreme as (or more extreme than) the one computed, assuming the null hypothesis (H₀) is true. If this probability is lower than your chosen significance level (α, e.g. 0.05), the result is statistically significant.

Conversely, the critical value is the value of the test statistic that separates the rejection region from the non-rejection region at your target alpha level. If your absolute test statistic is larger than the critical value, you reject the null hypothesis.