Repeated Measures ANOVA Flashcards
How do we sort variability between subjects?
Random sampling to cancel out individual characteristics
What are the sources of variance?
Experimental manipulation
Individual differences is cancelled out by repeatedly testing same ppts
What are the benefits of repeated measures testing?
Increased sensitivity
Economy - fewer ppts needed
What is the df calculation?
(No treatment) x (no ppts)
How do you calculate within-subjects model variability?
Calculate variability of each subject around their own mean and sum them all up
What is the sphericity assumption?
Variance of the difference across pairs of conditions should be almost the same
Assessed with Mauchlys test - p<.05 sphericity violated, p>.05 sphericity not violated
What are corrections for the violation of the sphericity assumption?
Greenhouse-Geisser
Huynh-Fieldt estimate
Rely on adjusting df
What are post-hocs for repeated measure ANOVAs?
Compare all pairs of means
Some more conservative than others e.g. Bonferroni > Holm
Many posthocs based on t tests with adjusted p value
What is needed to carry out mauchleys test?
3+ groups
How do calculate MS?
Adjust SS model/ residual by df
Why does residual error differ?
Lower due to individual differences factored out
What does the x*x column show?
2IVs interact with each other
Effect of 1 IV significantly depends on another
