Repeated Measures ANOVA (Free Access)

Repeated Measures of ANOVA

  • Used when the research involves changes in mean scores over three or more time points, or when differences in mean scores under three or more different conditions/groups.
  • Method:
    • Analyze
    • General Linear Model
    • Repeated Measures
    • Rename within subject factor name with IV
    • Add number of groups in the number of levels section
    • Add DV in the measure name section
    • Click on Define
    • Move the relevant groups to the section under within-subject variables
    • Plots
  • Move the IV to the horizontal axis
  • Click continue
  • Options
  • Move IV
  • Click on descriptive stats and estimates of effect size
  • Click compare main effects and select Bonferroni

Output:

  • If Mauchy‚Äôs test for sphericity is significant, it means that the assumption of sphericity has been violated and score from Greenhouse-Geisser can be checked
  • If the scores on Greenhouse-Geisser are significant, then the differences in the 3 levels of the IV are significant.
  • If you look at the table of pairwise comparisons you can see the differences between any two groups of the 3 tested. If they are significant you can conclude that two groups differed significantly from one another at a certain level