T-Test Calculator

Run a one-sample, two-sample pooled, or Welch t-test from summary statistics. Get the t statistic, degrees of freedom, and two-tailed p-value with a plain-language significance note at alpha 0.05.

Test mode

Sample meanSample standard deviationStandard deviation of the data, greater than 0.Sample size (n)Whole number of observations, at least 2.Population or target meanThe value you are testing the sample mean against.

t statistic

2.5

Degrees of freedom

Two-tailed p-value

0.019654

Standard error

0.4

Significance at 0.05: The p-value is below 0.05, which suggests the difference is statistically significant at the 0.05 level.

Two-tailed p-values come from the Student t-distribution using the regularized incomplete beta function: p = betai(df/2, 0.5, df/(df + t*t)).