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 ...

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 ...

What is a one sample t test? The t test is a commonly used hypothesis test in statistics that allows us to compare the mean value of a group of sampled data with some hypothesized value, usually a ...