Sample size requirements for reliability studies.

This paper provides exact power contours to guide the planning of reliability studies, where the parameter of interest is the coefficient of intraclass correlation rho derived from a one-way analysis of variance model. The contours display the required numbers of subjects k and number of repeated measurements n that provide 80 per cent power for testing Ho: rho less than or equal to rho 0 versus H1: rho greater than rho 0 at the 5 per cent level of significance for selected values of rho o. We discuss the design considerations of these results.