Other Sites


  1. Introduction 
  2. Factors affecting power
    1. Introduction
    2. Size of difference between means
    3. Significance level
    4. Sample size
    5. Variance
    6. Other factors
  3. Estimating power
  4. Exercises

Precision Consulting

Analysis Tools
Power analysis for numerous designs and statistics
John Pezzullo

Power analysis for ANOVA designs
by Michael Friendly

Statistical considerations for clinical trials and scientific experiments
by David Schoenfeld

Power and sample size page
by Russ Lenth

Instructional demos

Power Applet

Power analysis
by StatSoft

Sample size, power and precision (PDF)
by B. Gerstman

Difference between means: Type I and Type II errors and power
by T. D. V. Swinscow; revised by M. J. Campbell

Two sample size practices that I don't recommend (pdf file)
by Russ Lenth

The ideas behind statistical power
by N. Scott Urquhart

Important Factors in Designing Statistical Power Analysis Studies
by Robin High

Power Analysis for Regression and Stepwise Regression
by David C. Howell

Identification of Misconceptions in Learning Statistical Power with Dynamic Graphics as a Remedial Tool
by Chong Ho Yu and John T. Behrens


Statistical Power Analysis : A Simple and General Model for Traditional and Modern Hypothesis Tests
by Kevin R. Murphy and Brett Myors (Editor)

Statistical Power Analysis for the Behavioral Sciences
by Jacob Cohen

How Many Subjects : Statistical Power and Analysis in Research
by Helena Chmura Kraemer and Sue Thiemann