What is the westermarck effect?

What is an interaction of a main effect?

• What does this mean, my teacher sent it and I don't want to bother him again. An interaction qualifies a main effect. Imagine you had a main effect of word length (as you do, I think), but that it interacted with presentation time. This would mean that the effect of word length differed across the two levels of presentation time (e.g., if word length had a large effect with the short presentation, but no effect with the long presentation).

• Answer:

  Factorial analysis of variance (ANOVA) question. It's not exactly an "interaction of a main effect", but an interaction effect versus a main effect In the presence of a significant interaction effect, you will NOT interpret a main effect of an independent variable (the effect of the variable alone), even if the main effect shows up as statistically signficant. The effect of "word length" is mediated by the interaction of "word length x presentation time" In your example, you don't define your outcome/dependent variable, so I can't give a lot of precision, and will call it "outcome X". However, you have two independent variables: word length and presentation time, that are being analyzed to determine their relative effects on "outcome X". As far as I can go with your information: The independent variable "word length" (probably classified into two levels such as "short words" versus "long words" or something similar) has a large effect on "outcome X" when the presentation is short, but no effect when the presentation is long. Thus, even if "word length" shows up as having a signficant effect on "outcome X" in the table, you can't conclude that it is actually signficant by itself unless there are no "word length x presentation time" effects. That's what "qualifies" means here. I hope that helps -- it would be easier if I could present an ANOVA table on here and discuss constants and so forth