ABSTRACT
Precision analyses (also known as accuracy in parameter estimation) focus on the width of confidence intervals (CIs). Precision analysis provides information that supplements power analyses and in some cases is more appropriate to research goals. This chapter covers precision for mean differences, standardized mean differences (i.e., Cohen’s d), correlations, and R 2 values in multiple regression. The chapter also presents strategies for using precision approaches to “support” null hypotheses. For each analysis, the chapter presents examples using R functions from the pwr2ppl package.
