ABSTRACT
The statistical power of a study design is the capability of that study design to correctly identify a real effect when it occurs. Think of power as the amount of magnification a study has to see the effect under the microscope. Power is influenced by three things: the size of the effect being studied, the size of the sample, and the statistical significance level that is chosen. This chapter investigates the effects of hypnosis on sports performance. The majority of the controlled studies can be characterized as possessing limited statistical power, with four of the six studies incorporating 15 or fewer participants per experimental condition. Power is an important statistical consideration. Power is the probability that a statistical test will reject the null hypothesis when the null hypothesis is false. Statistical power analysis with Microsoft Excel: normal tests for one or two means as a prelude to using non-central distributions to calculate power.
