PSY 350 Lecture Notes - Lecture 41: Factorial Experiment, Complement Factor B, Dependent And Independent Variables
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We use separate lines to represent the levels of the other independent variable. If the lines are clearly separated, that indicates a main effect for the iv represented by the lines. When we have additive main effects, we get parallel lines. The effect (slope or separation) of one variable doesn"t change based on the level of the other one. **when the slopes aren"t parallel, it is an interaction. In a disordinal interaction, the directioon of the effect of one iv completely reverses at some levels of the other iv. One is a positive slope, one is a negative slope. In a line graph, this shows up as crossed lines. Identify situations in which a two-way anova is appropriate. This is not the same things as saying we have two levels of one factor. We are interested in the effects of both factors on the same dependent variable. Usually, we design the study carefully so that this is impossible.
