Contents

258 PART III: Experimental MethodsSTRETCHING EXERCISE IIIn this exercise you will have the opportunity topractice identifying main effects and interactioneffects in 2 2 complex designs using only descriptivestatistics.In the spirit of practice makes perfect, let usnow turn our attention to the exercise we haveprepared to help you learn to identify main effectsand interaction effects. Your task is to identifymain effects and interaction effects in each ofsix complex design experiments (A through F).In each table or graph in this box, you are todetermine whether the effect of each independentvariable differs depending on the level ofthe other independent variable. In other words,is there an interaction effect? After checking forthe interaction effect, you can also check to seewhether each independent variable produced aneffect when collapsed across the other independentvariable. That is, is there a main effect ofone or both independent variables? The exercisewill be most useful if you also practice translatingthe data presented in a table (Figure 8.2) intoa graph and the data presented in graphs (Figures8.3 and 8.4) into tables. The idea of the exerciseis to become as comfortable as you canwith the various ways of depicting the results ofa complex design.FIGURE 8.2Mean number of correct responses as a function of task difficulty and anxiety level.A. Task DifficultyB.Task DifficultyEasyHardEasyHardAnxiety LevelHigh Low3.33.35.6 1.2Anxiety LevelHigh Low6.23.14.2 1.1FIGURE 8.3Mean number of aggressive responses as a function of type of media and content.Mean Number AggressiveResponsesC.543210ViolentNonviolentTV Video GameType of MediaMean Number AggressiveResponsesD.543210ViolentNonviolentTV Video GameType of Media