Which of the following correctly explains why we use partial estimates of eff ect size for a within-subjects design?

a. To compute proportion of variance for a within-subjects design, we partial out the between-subjects variability because this variability was removed from the test statistic for a one-way within-subjects ANOVA.

b. To compute proportion of variance for a within-subjects design, we partial out the within-groups variability; for a between-subjects design, there is no within-groups variability to partial out, which is why we only do this using a within-subjects design.

c. To compute proportion of variance for a within-subjects design, we partial out the between-persons variation because this variability was removed from the denominator of the test statistic for a one-way within-subjects ANOVA.