What Is the Probability of Rejecting the Null Hypothesis?: Statistical Power in Research.

Power refers to the probability that a statistical test will yield statistically significant results. In spite of the close relationship between power and statistical significance, there is a consistent overemphasis in the literature on statistical significance. This paper discusses statistical significance and its limitations and also includes a discussion of statistical power in the behavioral sciences. Finally, some recommendations to increase power are provided, focusing on the necessity of paying more attention to power issues. Changing editorial policies and practices so that editors ask authors to estimate the power of their tests is a useful way to improve the situation. Planning research to consider power is another way to ensure that the question of the probability of rejecting the null hypothesis is answered correctly. Four tables and two figures illustrate the discussion. (Contains 28 references.) (SLD)