Maurice conducted a 2 x 2 completely within-subjects experiment. He counterbalanced all of his within-subjects conditions by making use of 24 different orders. If he used 24 different orders, which form of counterbalancing must he have used?

A public service advertisement intended to promote healthy habits which features young people having fun while eating healthy snacks and exercising has:

a. a positive valence. b. a negative valence c. no valence d. reactance

Which correlation should be used to measure the relationship between gender and grade point average for a group of college students?

a. Pearson correlation b. Spearman correlation c. Point-biserial correlation d. Phi-coefficient