chapter  7
Calculating F ratios for one-factor within-subjects designs
Pages 24

In this chapter, the basic ANOVA calculations introduced in Chapters 3 and 4 for the between-subjects design will be modified for within-subjects designs. For a within-subjects design, every subject takes part in all of the levels of a factor, and knowing more than one piece of information about every subject enables the size of the error term to be reduced for the F ratio. 1 This results in a larger value of F and hence the effect is more likely to be significant. Overall, for a given effect size and a given number of scores, any within-subjects design study should be more powerful than an equivalent between-subjects design.