11 Within-subject and mixed designs

Question 1

In mixed model ANOVA contrasts, the /WSFACTOR line means what?

Answer 1

A within-subjects (or repeated-measures) variable.

Question 2

In mixed model ANOVA contrasts, the /CONTRAST line means what?

Answer 2

A between-groups contrast.

Question 3

In mixed model ANOVA contrasts, the /lmatrix line means what?

Answer 3

Between-groups interaction contrast.

Question 4

In mixed model ANOVA contrasts, the /mmatrix line means what?

Answer 4

Within-groups interaction contrast.

Question 5

If the contrasts are in ______ form, the contrast estimate and the difference estimate will be the same.

Answer 5

If the contrasts are in standard form, the contrast estimate and the difference estimate will be the same.

Question 6

Why must you mean-centre covariates in ANOVA?

Answer 6

Because SPSS substitutes zero on the covariate. In other words, the estimates you get for the other variables are when the covariate is 0, so if you make 0 the mean of the covariate, your estimates are when other people score average on the covariate.