p
P-Value Calculator
The p-value for a z or t test statistic, one- or two-tailed.
Result…
How it's calculated
Two-tailed: p = 2 × P(T ≥ |t|) Right-tailed: p = P(T ≥ t) Left-tailed: p = P(T ≤ t)
The p-value is the chance of a statistic at least this extreme if the null hypothesis were true. A small p-value is evidence against the null, not the probability that it is true, and it says nothing about how large or important an effect is. Pick one or two tails before looking at the data.
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