Student's t-test

A statistical hypothesis test that uses a t-distribution to assess whether a sample mean or difference between means departs from a specified value. It is especially useful when population variance is unknown.

t-statistic: A standardized statistic formed by dividing an estimated effect by its estimated standard error. The test converts a mean difference into this statistic before evaluating it against a t-distribution.
One-sample t-test: A t-test comparing one sample mean with a specified reference value. This is the direct form for testing whether a sample mean departs from a target.
Confidence interval: An interval estimate produced by a procedure designed to cover a parameter at a stated long-run frequency. A t-based interval expresses plausible values for a mean or mean difference alongside a test.
William Sealy Gosset: An English statistician who developed the t-distribution while working for the Guinness brewery. Gosset published the method under the pseudonym Student.
Degrees of freedom: The number of independent quantities available to vary in a statistical calculation. They determine the t-distribution's shape and often depend on sample size.
Independent-samples t-test: A t-test comparing means from two independent groups. It tests a difference between groups whose observations do not occur in matched pairs.
Effect size: A quantitative measure of the magnitude of a phenomenon or difference. A small p-value does not show whether the tested mean difference is practically substantial.
Student (pseudonym): The pen name William Sealy Gosset used for his statistical publications. The test's conventional name comes from Gosset's published pseudonym.
Null hypothesis: A statistical claim treated as the reference hypothesis in a significance test. A t-test measures how incompatible the observed data are with this specified claim.
Paired t-test: A t-test applied to differences between paired observations. Repeated measurements or matched subjects become one sample of within-pair differences.

Linked from 8 pages