Sample Size Calculation

Description

Sample size calculation estimates the number of study participants needed to detect a specified effect with adequate statistical power while controlling error rates. Key inputs include expected effect size, variability, significance level (α), desired power (1−β), allocation ratio, and anticipated dropout rate. Larger effect sizes or higher tolerable error need fewer subjects, whereas small effects or multiple subgroup analyses increase requirements. Proper calculation prevents underpowered studies, ethical waste, and excessive costs, ensuring scientifically valid, generalizable results and widely accepted conclusions.