The two-sample t-test is one of the most commonly used hypothesis tests in Six Sigma work. It is applied to compare the average difference between two groups. You use it to determine if the difference ...

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 ...