Sample Size Estimation and Power Analysis for Clinical Research Studies

J Hum Reprod Sci. 2012 Jan;5(1):7-13. doi: 10.4103/0974-1208.97779.

Abstract

Determining the optimal sample size for a study assures an adequate power to detect statistical significance. Hence, it is a critical step in the design of a planned research protocol. Using too many participants in a study is expensive and exposes more number of subjects to procedure. Similarly, if study is underpowered, it will be statistically inconclusive and may make the whole protocol a failure. This paper covers the essentials in calculating power and sample size for a variety of applied study designs. Sample size computation for single group mean, survey type of studies, 2 group studies based on means and proportions or rates, correlation studies and for case-control for assessing the categorical outcome are presented in detail.

Keywords: Correlation; odds ratio; power; prevalence; proportions; sample size; survey.

Publication types

  • Retracted Publication