ERIC Number: ED171787
Record Type: RIE
Publication Date: 1979-Apr-11
Reference Count: 0
Dependent Variable Reliability and Determination of Sample Size.
Maxwell, Scott E.
Arguments have recently been put forth that standard textbook procedures for determining the sample size necessary to achieve a certain level of power in a completely randomized design are incorrect when the dependent variable is fallible because they ignore measurement error. In fact, however, there are several correct procedures, one of which is the standard textbook approach, because there are several ways of defining the magnitude of group differences. The standard formula is appropriate when group differences are defined relative to the within-group standard deviation of observed scores. Advantages and disadvantages of the various approaches are discussed, especially Subkoviak and Levin's alternative formula. Although all of the approaches discussed are mathematically correct, the traditional approach seems most meaningful; it is recommended that researchers continue to use this formula to determine statistical power and required sample size. (Author/GDC)
Publication Type: Speeches/Meeting Papers; Reports - Research
Education Level: N/A
Authoring Institution: N/A
Note: Paper presented at the Annual Meeting of the American Educational Research Association (63rd, San Francisco, California, April 8-12, 1979)