Flashcards in Repeated Measures ANOVA Deck (18)
What is a Repeated Measures ANOVA?
When there are 3+ within-subject conditions. Looking at differences.
What is a strength of a Repeated Measures ANOVA?
No increase of Type I Error (family-wise error).
What is a disadvantage of a Repeated Measures ANOVA?
Can determine if there's a difference but not which conditions actually differ. Need follow-up tests for this.
What is a weakness of a T-Test?
The family-wise error. Each additional T-Test increases chance of Type I error.
Define systematic variation & unsystematic variation.
Systematic variation is the variation due to our manipulation.
Unsystematic variation is the variation due to random factors.
What is the concept behind an ANOVA?
It breaks down the total variance (systematic + unsystematic) and compares the two sources.
When do we know that the IV affected the DV?
When the systematic variation is larger than the unsystematic variation.
What is SSbc?
The estimated variation in scores between conditions.
What is SSwc?
The estimated variation in scores within conditions.
What is SSbs?
The estimated variation in scores between participants.
How do you calculate DFbc?
k-1. Where k is the number of conditions.
How do you calculate DFerror?
(n-1)(k-1). Where k is the number of conditions.
How do you calculate F?
F = MSbc / MSerror. Where MSbc is SSbc / DFbc and MSerror is SSerror / DFerror.
What does a large F-value show?
That a large ratio of our variance is due to our manipulation.
What is sphericity?
Assumption that the variance of difference between pairs of conditions is the same.
What test is used to test for sphericity?
Mauchly's Test (must be non-significant).
What results do you read off if sphericity isn't met?