The rest of the article, however, discusses understanding the two-sample t-test, which is easy to use but not so easy to understand. If one subtracts the means from two samples, in most cases ...

A t-test for population means compares the means between two populations. It is appropriate when the population standard deviations are unknown. This applet allows users to change the distributions of ...

test groups, and between and among groups. ANOVA is like several two-sample t-tests. However, it results in fewer type I errors. ANOVA groups differences by comparing each group's means and ...

A two-sample z-test for population means compares two population means. It is appropriate when the population standard deviations are known and the sample sizes are large. This web calculator conducts ...