Two Sample Z-Test Calculator

Two sample z-test is used to test whether the means of two populations are equal. It is used when the population standard deviations are known.

Either enter raw data or summary information in the calculator below to calculate a two sample z-test. You can directly paste data from MS Excel.

Enter Raw Data

Population 1 Standard Deviation ($ \sigma_{1} $) Population 2 Standard Deviation ($ \sigma_{2} $)

Enter Summary Data

Sample1 mean ($ \bar{x}_{1} $) Sample1 Size ($ n_{1} $) Sample2 mean ($ \bar{x}_{2} $) Sample2 Size ($ n_{2} $) Population 1 Standard Deviation ($ \sigma_{1} $) Population 2 Standard Deviation ($ \sigma_{2} $)

Result

Assumptions of Two Sample Z-Test

Data in each population should be approximately normally distributed.
Each score is sampled independently and randomly.
Z-Test assumes you know the population standard deviations for both groups.