A one-factor within-subjects analysis of variance tests the null hypothesis that all the population means are equal: H

In a between-subjects ANOVA, variance due to differences among subjects goes into the error term. In within-subjects ANOVA, differences among subjects can be separated from error. "Subjects" is therefore a source of variation in within-subjects designs. The analysis of variance summary table for the data given in the section on the advantages of within-subjects designs is shown below. Notice the three sources of variation: Subjects, Condition, and Error.

Source df Ssq Ms F p Subjects 3 1888.375 629.458 Condition 1 15.125 15.125 121.00 0.002 Error 3 0.375 0.125 Total 7 1903.875 271.982