Sample size calculation and power analysis: a quick review

Abstract

Diabetes educators conducting research need a basic understanding of statistical concepts so study findings are useful and can be read with confidence. Selecting an adequate sample size is a key step that needs to be considered early in the process of designing a research study. A sample size too small will not provide reliable answers to the study questions asked or research hypotheses needing to be tested. A sample size that is too big can make the study unwieldy, wasting both time and effort. An adequate sample size uses resources and time in the most cost-effective manner and is essential to producing useful research findings. The purpose of this article is to understand the importance of selecting an adequate sample size in gaining information from a small group (sample) that can be generalized to a larger group (population) along with discussing power analyses.