Statistics for Sport and Exercise Studies

CHAPTER 20

STATISTICAL POWER

INTRODUCTION

Statistical power analysis is an area of statistics that warrants a book in its own right. For a full coverage of statistical power analysis, the author recommends Murphy et al.’s (2009) textbook on the area. This chapter will briefly cover statistical power, Murphy et al.’s (2009) model and the four applications of power analysis.

WHAT IS STATISTICAL POWER?

Statistical power is the conditional probability of finding a significant difference or relationship in a sample when such a difference or relationship exists in the population from which the sample is drawn. A power of 0.2 indicates that a study is four times as likely to accept the null hypothesis than to reject it when the null is actually false ...