East Carolina University
Department of Psychology
G*Power, Version 3.1 -- - free, easily downloadable power analysis program.
Faul, F., Erdfelder, E., Buchner, A., & Lang, A.-G. (in press). Statistical power analyses using G*Power 3.1: Tests for correlation and regression analyses. Behavior Research Methods
Faul, F., Erdfelder, E., Lang, A.-G., & Buchner, A. (2007). G*Power 3: A flexible statistical power analysis program for the social, behavioral, and biomedical sciences.
Version 3.1 was released in
June of 2009. Added were procedures to analyze the power of tests
referring to
(1) single correlations based on the tetrachoric model,
(2) comparisons of dependent correlations,
Two dependent Pearson r's (common index)
Two dependent Pearson r's (no common index)
Two independent Pearson r's
(3) bivariate linear regression,
One group, size of slope
Two groups, difference between intercepts
Two groups, difference between slopes
(4) multiple linear regression based on the random predictor model,
(5) logistic regression, and
(6) Poisson regression.
Other Software
Bakeman Programs - power for multiple regression, some other programs too
G*Power Version 2 - GP-Setup.exe is the installation program for Windows computers.
PS: Power and Sample Size Calculation - comparisons of slopes and intercepts from independent regressions (and more)
R2: Steiger and Fouladi -- Multiple correlation.
Sample Size Calculation, Binomial -- determine number of observations necessary to obtain CI of desired width, estimating binomial p.
Teach or Learn About Power Analysis
Claremont Power Applet - illustrate effect of various parameters on power -- null is MU1 > MU0.
JSE Article on Teaching Power - using Java applets.
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Contact Information for the Webmaster,
Dr. Karl L. Wuensch
This page most recently revised on the 3rd of November, 2011.