A researcher has used a complex design to study the effects of training (untrained and trained) and problem difficulty (easy and hard) on participants’ problem-solving ability. The researcher tested a...

A researcher has used a complex design to study the effects of training (untrained and trained) and problem difficulty (easy and hard) on participants’ problem-solving ability. The researcher tested a total of 80 participants, with 20 randomly assigned to each of the four groups resulting from the factorial combination of the two independent variables. The data presented below represent the mean percentage of the problems that participants solved in each of the four conditions.

A Is there evidence of a possible interaction effect in this experiment?

B What aspect of the results of this experiment would lead you to be hesitant to interpret an interaction effect if one were present in this experiment?

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