Question

A researcher has used a complex design to study the effects of caffeine (caffeinated and decaffeinated) and problem difficulty (easy and hard) on subjects’ memories. The researcher tested a total of eighty subjects, with twenty subjects randomly assigned to each of the four groups resulting from the factorial combination of the two independent variables. The data presented in the table represent the percentage words that subjects recalled correctly in each of the four conditions.

Caffeine
Problem difficulty	Caffeinated	Decaffeinated
Easy	99	85
Hard	95	70

1. Is there evidence of a possible interaction in this experiment?

2.What aspects of the results of this experiment would lead you to be hesitant to interpret an interaction, if one were present in this experiment?

3.How could the researcher modify the experiment so as to be able to interpret an interaction if it should occur?

Answer 1