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  3. Intro to Statistics with R: Analysis of Variance (ANOVA)

Exercise

The interaction effect (1)

Now it's time to explore the interaction effect. You will do this with the help of a simple effects analysis.

Why a simple effects analysis? Well, remember what you had to do when you had a significant main effect in a one-way ANOVA? There, you just had to perform some post-hoc tests to see from which level of the categorical variable the main effect was coming. With an interaction effect, it is quite similar. Conduct a simple effects analysis of the variable conversation on the outcome variable errors at each level of driving.

Instructions

100 XP
  • Create a subset ab_1 from ab where driving difficulty equals "Easy".
  • Create a subset ab_2 from ab where driving difficulty equals "Difficult".
  • Perform a one-way ANOVA for the effect of conversation on driving errors for both ab_1 and ab_2. Assign the results to aov_ab_1 and aov_ab_2, respectively.
  • Print the summary table for both aov_ab_1 and aov_ab_2 and study the output carefully.