SPSS MIXED: Pairwise comparisons on interaction covariate (continuous) x factor (categorical)

Question

I have 77 subjects, 1 continuous DV (activation), 2 continuous IVs (score1 and score2) and 1 categorical IV (condition) with 2 levels. Each subject undergoes both conditions.

I code the model as:

MIXED activation BY condition WITH score1 score2 
  /CRITERIA=CIN(95) MXITER(1000) MXSTEP(10) SCORING(1) SINGULAR(0.000000000001) HCONVERGE(0, 
    ABSOLUTE) LCONVERGE(0, ABSOLUTE) PCONVERGE(0.000001, ABSOLUTE) 
  /FIXED=condition score1 score2 condition*score1 condition*score2 | SSTYPE(3) 
  /METHOD=ML 
  /PRINT=DESCRIPTIVES G  SOLUTION TESTCOV 
  /REPEATED=condition | SUBJECT(subject) COVTYPE(ID) 
  /EMMEANS=TABLES(condition) COMPARE ADJ(BONFERRONI)

Which commands should I use to investigate the interaction between condition(0, 1) and score1 (continuous)?

score 0 · Answer 1 · answered Mar 27 '20 at 19:46

If you can get the regression coefficients for the fixed part of the model, the one for condition*score1 will equal the difference between the score1 slopes between the two conditions. That will provide a test of the null hypothesis that the slopes are equal, I.e., that the score1 effects are the same.

Use the analogous method for condition*score2.

SPSS MIXED: Pairwise comparisons on interaction covariate (continuous) x factor (categorical)

1 Answers1