Analysis of Covariance (ANCOVA)

· A student has informed me that after updating the SPSS license the General Linear Model-->Univariate was not available in the GUI (the point-n-click). If you are having a similar issue, please try to run the following syntax to obtain your output. You will need to open the dataset and a new syntax window and paste the following syntax (not the headings) and run the analysis.

Independence of IV and covariate

 

UNIANOVA stalk1 BY group

  /METHOD=SSTYPE(3)

  /INTERCEPT=INCLUDE

  /PLOT=PROFILE(group)

  /EMMEANS=TABLES(OVERALL)

  /EMMEANS=TABLES(group) COMPARE ADJ(BONFERRONI)

  /PRINT=ETASQ HOMOGENEITY DESCRIPTIVE

  /CRITERIA=ALPHA(.05)

  /DESIGN=group.

 

Homogeneity of regression assumption

 

UNIANOVA stalk2 BY group WITH stalk1

  /METHOD=SSTYPE(3)

  /INTERCEPT=INCLUDE

  /PLOT=PROFILE(group)

  /EMMEANS=TABLES(OVERALL) WITH(stalk1=MEAN)

  /EMMEANS=TABLES(group) WITH(stalk1=MEAN) COMPARE ADJ(BONFERRONI)

  /PRINT=ETASQ HOMOGENEITY DESCRIPTIVE

  /CRITERIA=ALPHA(.05)

  /DESIGN=group*stalk1 group stalk1.

 

Final Model

 

UNIANOVA stalk2 BY group WITH stalk1

  /METHOD=SSTYPE(3)

  /INTERCEPT=INCLUDE

  /PLOT=PROFILE(group)

  /EMMEANS=TABLES(OVERALL) WITH(stalk1=MEAN)

  /EMMEANS=TABLES(group) WITH(stalk1=MEAN) COMPARE ADJ(BONFERRONI)

  /PRINT=ETASQ HOMOGENEITY DESCRIPTIVE

  /CRITERIA=ALPHA(.05)

  /DESIGN=stalk1 group.