How Large Should the Sample be? A Question with no Simple Answer? or...

Abstract
A recurring problem in behavioral science research is that of determining the appropriate sample size before conducting a research investigation. The more common approaches to this problem have been to apply indiscriminantly the formulae used in survey research without considering the factors necessary for using these formulae. The most important of these factors is the Effect Size. In this paper, tables for the appropriate sample sizes are presented and discussed in the context that the determination of the Effect Size must precede the determination of the sample size.