justyourcalculatorP-Value Calculator
Turn a test statistic into a p-value and a clear yes or no.
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P-Value Calculator
P-values from z, t, chi-square and F
P-value (two-tailed)
0.049996
Significant at α = 0.05: reject the null hypothesis.
- Left-tailed p-value
- 0.975002
- Right-tailed p-value
- 0.024998
- Two-tailed p-value
- 0.049996
How it was calculated
- Distribution: standard normal
- Left tail P(X ≤ 1.96) = 0.975002
- Right tail P(X ≥ 1.96) = 0.024998
- Two-tailed = 2 × min(left, right) = 0.049996
- 0.049996 < α = 0.05
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How the p-value calculator works
A p-value is the probability of getting a test statistic at least as extreme as the one you observed, if the null hypothesis were true. Small p-values (below your significance level α, often 0.05) are evidence against the null hypothesis.
Right-tailed tests use the area above the statistic, left-tailed the area below, and two-tailed tests double the smaller tail. Chi-square and F tests are almost always right-tailed.
The z p-value uses the normal distribution, t uses Student's t with its degrees of freedom, chi-square uses the regularized incomplete gamma function, and F the regularized incomplete beta function, each computed to about 12 significant digits.
Using and checking your result
Published by JustYourCalculator. Check the units and assumptions above, and compare a known example before relying on the output. Calculations use browser arithmetic and may round displayed values.
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