ABSTRACT
This chapter begins with a review of null hypothesis significance testing and effect sizes. The chapter then focuses on factors that influence power and discusses the importance of power in research design and sample size planning. Additional sections present an introduction to noncentral distributions, address misconceptions about power, discusses typical levels of power in published work, examines strategies for determining an appropriate effect size for power analysis, critiques post hoc power analyses, and discusses typical levels of power used for design. New sections address the role of statistical power in the reproducibility crisis and how editors are responding to these issues with renewed calls for increased attention to statistical power in research design.
