Repeated-measures ANOVA is best described as:

• A. An analysis of variance conducted on designs in which the independent variable (predictor) or predictors have all been measured using the same participants in all conditions.
• B. An analysis of variance where different participants are used in each condition.
• C. An analysis of variance with only between-subjects factors.
• D. A regression technique for non-linear data.

Answer: (C)

Repeated-measures ANOVA is used when the same participants are measured in every condition. This within-subjects design means each person contributes multiple observations, which helps control for individual differences and reduces error variance, increasing the ability to detect differences across conditions. Because measurements from the same person are linked, the analysis accounts for the resulting correlation between their scores. If the data violate the sphericity assumption, you can apply corrections like Greenhouse-Geisser. Designs that use different participants in each condition describe between-subjects designs, not repeated-measures. Regression is a different analysis framework and does not describe this design.