Week 2 ANOVA

Question 1

When do you use ANOVA?

Answer 1

• prediction
• between groups
• 1 Y

Question 2

how to check if ANOVA test is robust to violations of group normality?

Answer 2

check if in every group N>=15

Question 3

how to check if ANOVA is robust to violations of heterogene groupvariances?

Answer 3

Nmax/Nmin=<1.5

Question 4

how to check for normality in ANOVA?

Answer 4

see Histogram of std residuals

Question 5

what is the rule of tumb when checking for homogene groupvariances in ANOVA?

Answer 5

• rule of thumb: biggest SD/ smallest SD= <=2=homo

Question 6

what can we see in this table?

ANOVA

Answer 6

• check if Y and X(en) have no relationship (corrected model)
• check if one of the X’s has an effect on Y (strategy, gender)
• check if there is an interaction effect between X’s

let op noteer df effect, df error F en p
vb
F (3, 38) = 5.955, p = .002

Question 7

what can we check in this table?

Answer 7

• check for equal group variances
• see mean
  we want it to be NOT significant, because we want it to be equal.

Question 8

what can we check in this table?

ANOVA

Answer 8

if effect x on y or interaction is sign than we can check
* which group (within one x) has the highest or lowest score on Y
* if there is a difference between groups between X’s (interaction). We can visualise this effect by checking the profile plot

Question 9

how to determine variance accounted for (VAF) for each sign predictor?

Answer 9

eta squared. zie blaadje.

Question 10

what can we check in this tukey post hoc test table?

Answer 10

if effect of x on y is sign.
* which group has sign different EMM’s