| Abstract: | The statistical theory of the power of significance tests, combined with the classical theory of the reliability of measurement, reveals that the power of a statistical test sometimes increases and sometimes decreases as the reliability coefficient of a dependent variable increases. This seeming paradox arises because the relation between statistical power and the reliability coefficient is not a functional relation unless another variable—either true variance or error variance—remains constant. The authors show that the paradox disappears if widely accepted, elementary results in statistical theory and measurement theory are considered together. This approach explains why some authors have reached different conclusions about how reliability influences significance tests. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) |
