About the P-Value Calculator
Convert a z, t, chi-square, or F statistic into an accurate p-value with a visual.
What it is
Once you've computed a test statistic, the last step in a hypothesis test is finding its p-value โ traditionally done by looking up a printed table and interpolating. This tool computes the p-value directly using accurate cumulative distribution function approximations, for the four statistics used across most introductory and intermediate statistics courses.
Features
Four statistic types
Z, T, chi-square, and F, each with the appropriate degrees-of-freedom inputs.
Tail selection
Left, right, or two-tailed for z and t; chi-square and F default to right-tailed as is standard.
Shaded distribution graph
A live canvas plot of the relevant distribution with the p-value region shaded.
Accurate CDF implementations
Uses the incomplete beta and incomplete gamma functions for the t, chi-square, and F distributions.
Significance flags
Instantly see whether your result is significant at ฮฑ = 0.05, 0.01, and 0.001.