ANOVA Flashcards
What is S^2 within?
The within-groups estimate of the population variance
What is S^2 between?
Between-groups estimate of the population variance
What is SStotal?
Total sum of squares
What is SSbetween?
Between-groups sum of squares
What is SSwithin?
Within-groups sum of squares
What is dftotal?
Total degrees of freedom
what is dfbetween?
Between-group degrees of freedom
Is dfbetween always on the numerator or denominator?
Numerator
What is dfwithin?
Within-groups degrees of freedom
Is dfwithin always on the numerator or denominator?
Denominator
How many IV’s are in a one way ANOVA?
One
Nominally scaled
Three or more levels
What do you assume about the populations in a one way ANOVA?
They’re normal, have equal variances and independent scores
How many dependent variables does a one way ANOVA have?
One
What scale of measurement does the DV have in a one way ANOVA?
Equal interval
Step one of one way ANOVA
Restate the question as a research and null hypothesis
What is the null hypothesis in a one way ANOVA?
Mew1 = mew2 = mew3
What is the research hypothesis for a one way ANOVA?
The population means differ in some way
- cannot be written in symbols
What is type 1 error in a one way ANOVA?
The probability of rejecting the null hypothesis when it is true
S^2 within in a one way ANOVA
Looks at variance within each sample to estimate population variance
S^2 between in one way ANOVA
Looks at variance between samples to estimate population
What happens in a one way ANOVA if there’s no treatment effect and the null is true?
S^2 within = S^2 between
What happens in a one way ANOVA if there’s a treatment effect and the null is false?
S^2 between > S^2 within
What is an F ratio in a one way ANOVA?
Comparison of the two population variances
What will the F ratio be when there’s no treatment effect and the null is true?
Close to 1
What will the F ratio be when the null is false and there’s no treatment effect?
Greater than 1
Numerator of the F ratio dfbetween
N groups - 1
Denominator of the F ratio dfwithin
Df1 + df2 +df3
What is a grand mean
The overall mean of the means
How to measure SSbetween
How much does each mean deviate from the grand mean?
Calculate SSwithin
How much do individual scores deviate from the mean of each group?