P-Value Calculator
Statistics & ProbabilityCompute exact one-tailed and two-tailed p-values from test statistics (Z-score, Student's t, Chi-Square, F-distribution) to evaluate hypothesis test statistical significance.
P-value · Statistically significant at α = 0.05
About this calculator
In scientific research and A/B testing, the p-value measures the probability of observing test results at least as extreme as the actual observed sample data, assuming the null hypothesis is true.
This calculator converts raw test statistics (Z, t with degrees of freedom, Chi-Square with df, and F with numerator/denominator df) into precise one-tailed and two-tailed p-values, highlighting whether results meet α = 0.05 or α = 0.01 significance thresholds.
How It Works & Formula
P-values are computed from the cumulative distribution function (CDF) of the respective probability distribution: for standard normal, p_two_tail = 2 × (1 - Φ(|z|)); for Student's t, incomplete beta regularized functions evaluate tail probabilities.
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