ANOVA

Question 1

ANOVA

Answer 1

Compare variability within group with variability btw group

Question 2

F Test

Answer 2

DF:
SStotal: n-1
SSbtw: g-1
SSwithin: n-g

If signif -> means are different
The larger F the less likely H0 the lower the p-value

F-value = Mean Sq : Res Mean Sq
Mean Sq = Sum Sq : Df

-> if there is a significant interaction term, p values of Haupteffekte nicht interpretierbar

Question 3

Post hoc Tests (which of the groups deviates from others)

Answer 3

• Bonferroni corr.
• Tukey honest significant differences (HSD)
• Fisher least significant differences (LSD)

-> contrasts (tTest) -> apriori

Question 4

Check for NAs

Answer 4

na.omit(dd)
If still same number of rows -> no NAs

Question 5

Which is based on a linear model

Answer 5

• Multiple linear model
• linear regression
• ANOVA
• t test
• ANCOVA

Question 6

What can be done with lm() function

Answer 6

• linear regression
• ANOVA
• t-test
• multiple linear regression
• linear model with log transformation
• ANCOVA
• linear model with quadratic/cubic term