This statistic is a measure on a random sample (or pair of samples) in which a mean (or pair of means) appears in the numerator and an estimate of the numerator's standard deviation appears in the denominator. The latter estimate is based on the calculated s² or s²s of the samples.

If these calculations yield a value of (t) that is sufficiently different from zero, the test is considered to be statistically significant.

This is the formula for the statistic t when it is used to test the statistical hypothesis that two random samples come from populations with means equal to