Comparison of Significance Tests for Repeated Measures ANOVA Design

Abstract

The purposes of this study were (1) to compare the use of the usual F test, Box's approximate test, and the Geisser-Greenhouse conservative test for significance testing of the repeated measures ANOVA design, and (2) to describe the appropriate application of these techniques using motor performance data. The usual F test was conducted and the F value was significant. Then the conservative test was used to compute a new critical value and the F value was nonsignificant. Thus it was necessary to estimate theta (θ) using the Box approximation and compute another critical value, and this F value was significant. Therefore, the significance of the between trials effect could be interpreted as an indication of true differences between trials rather than a result of violating the assumption of covariance, thereby increasing the risk of obtaining significant results by chance.