Written by Ronny Gunnarsson and first published on November 17, 2014.
Last revised on June 13, 2020.

There is an updated version of the EPV-calculator found here: https://infovoice.se/epv-calculator/

Suggested pre-reading	What this web page adds
Introduction to statistics Choosing statistical analysis Sample size estimation	This web-page provides an introduction to the statistical software GPower. Reading this will give you enough knowledge to be able to try doing simple things in GPower.

(Still under construction but there is some useful information below.)

G*Power is a software that can make sample size calculations and power estimations. It can manage most types of statistical tests except Cox regression. G*Power can be downloaded from Dussedorf University.

Examples for comparing two groups

Click to watch any of these videos.

Example 1 of sample size calculation for comparing two groups – T-test and Mann-Whitneys test

Example 2 of sample size calculation for comparing two groups – T-test and Mann-Whitneys test

Example for Logistic regression

Click to watch any of these videos.

Example of sample size calculation for unconditional binary Logistic regression when the independent variable is binary (such as gender)

There is an updated version of the EPV-calculator found here: https://infovoice.se/epv-calculator/