Why Does Using a Correlated-Groups Design Reduce Error Variability

Multiple Choice

Why does using a correlated-groups design reduce error variability?

A) The independent variable is stronger in a correlated-groups design than in a between-subjects design.
B) The dependent variable is stronger in a correlated-groups design than in a between-subjects design.
C) The correlated-groups design is better suited to multiple independent variables compared to the between-subjects design.
D) Error variability due to individual differences in participants is decreased in a correlated-groups design.