Statistical Power and Sample Size Calculation Tools

pwrss R package allows statistical power and minimum required sample size calculations for

• (1) testing a proportion (one-sample) against a constant,
• (2) testing a mean (one-sample) against a constant,
  
• (3) testing difference between two proportions (independent samples),
• (4) testing difference between two means/groups (parametric and non-parametric tests for independent and paired samples),
• (5) testing a correlation (one-sample) against a constant,
  
• (6) testing difference between two correlations (independent samples),
• (7) testing a coefficient (with standardized or unstandardized coefficients, with no covariates or covariate adjusted) in multiple linear regression, logistic regression, and Poisson regression,
• (8) testing an indirect effect (with standardized or unstandardized coefficients, with no covariates or covariate adjusted) in the mediation analysis (Sobel, Joint, and Monte Carlo),
• (9) testing an R-squared against zero in linear regression
• (10) testing an R-squared difference against zero in hierarchical regression
• (11) testing an eta-squared or f-squared (for main and interaction effects) against zero in analysis of variance (ANOVA) (could be one-way, two-way, and three-way),
• (12) testing an eta-squared or f-squared (for main and interaction effects) against zero in analysis of covariance (ANCOVA) (could be one-way, two-way, and three-way),
• (13) testing an eta-squared or f-squared (for between, within, and interaction effects) against zero in one-way repeated measures analysis of variance (RM-ANOVA) (with non-sphericity correction and repeated measures correlation),
• (14) testing goodness-of-fit or independence for contingency tables.
  Alternative hypothesis can be formulated as “not equal”, “less”, “greater”, “non-inferior”, “superior”, or “equivalent” in (1), (2), (3), and (4); as “not equal”, “less”, or “greater” in (5), (6), (7) and (8); but always as “greater” in (9), (10), (11), (12), (13) and (14).

If you find the package and related material useful please cite as:

• Bulus, M. (2023). pwrss: Statistical Power and Sample Size Calculation Tools. R package version 0.3.1. https://CRAN.R-project.org/package=pwrss

• Bulus, M., & Polat, C. (in press). pwrss R paketi ile istatistiksel guc analizi [Statistical power analysis with pwrss R package]. Ahi Evran Universitesi Kirsehir Egitim Fakultesi Dergisi. https://osf.io/ua5fc/download/