Analysis of variance (ANOVA) Flashcards
(12 cards)
What is Analysis of Variance (ANOVA)?
A statistical method used to investigate differences between means of 3 or more samples/groups.
When should ANOVA be used?
When testing relationships between a nominal variable with 3+ categories and an interval/ratio outcome variable.
What significance level is typically set in ANOVA?
5% (Alpha = 0.05).
What statistic is calculated to perform ANOVA?
F-statistic.
What does the F-statistic measure in ANOVA?
The variation between group means compared to the variation within each group.
What is the formula for the F-statistic?
F-statistic = Mean Square Between (MSB) / Mean Square Within (MSW).
What does the Sum of Squares (SS) Between measure?
How much the group averages differ from the overall average (grand mean).
What does the Sum of Squares (SS) Within measure?
How individual values within each group vary from their own group’s mean.
What is Eta Squared (η²)?
A measure of effect size for ANOVA that quantifies how much variability in the dependent variable is associated with group membership.
What is the formula for calculating Eta Squared?
η² = SS Between / SS Total.
What does a significant F-statistic indicate?
Evidence of differences in rating scores between the groups.
What is the implication of a small Eta Squared value despite a significant F-statistic?
There is an effect of group membership, but it may not be a good predictor of variability in the dependent variable.
