The primary reason why within subjects designs are preferred over between subjects designs is that
a. fewer participants are required.
b. there are no treatment order effects.
c. error variability is reduced.
d. the participants are less likely to figure out the purpose of the experiment.
Question 2
In a factorial design, an interaction between the factors occurs whenever ____.
a. the mean differences between the cells are not explained by the main effects
b. the mean differences between the cells are explained by the main effects
c. there are differences between the overall column means
d. there are differences between the overall row means