4  ANCOVA and (between-subjects) factorial ANOVA

4.1 Learning outcomes

After viewing the tutorial materials and following along with the demonstration, you can:

  1. Set-up, run and interpret factorial ANOVAs and ANCOVAs for between-subjects designs
  2. Check the assumptions of these tests

4.2 Datasets

This demonstration uses the datasets goggles and puppy_love which were prepared by Andy Field and included in Field, van Doorn and Wagenmakers (2025).

goggles contains (fictional) data from a 2 x 3 factorial design with 2 between-subjects IVs. IV1 is attractiveness of face stimulus (Attractive or Unattractive) and IV2 is dosage of alcohol (Placebo, Low, or High). Participants were assigned to either the placebo, low dose, or high does group and gave attractiveness ratings (DV) to either attractive or unattractive faces.

puppy_love contains (fictional) data from a design with one, 3-level, between-subjects IV (dose of puppies: Control, 15 minutes, and 30 minutes of puppy therapy) and one DV (Happiness after therapy, 0-10). The dataset also includes the covariate Love of puppies measured on a scale of 0-7.

4.3 Videos