Sample size calculations and power analysis

This fact sheet explains the role of sample size calculations and power analysis in the planning, interpretation, and reporting of quantitative research. It outlines the core inputs required for power analysis, including effect size, alpha, and desired power, and discusses how study design features such as repeated measures, measurement reliability, and covariate control influence statistical power. The document also addresses common misconceptions about pilot studies and post hoc power analysis, providing practical guidance to help researchers design adequately powered studies and interpret null findings appropriately.