27.03.2013 Views

SPSS® 12.0 Command Syntax Reference

SPSS® 12.0 Command Syntax Reference

SPSS® 12.0 Command Syntax Reference

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

GLM: Repeated Measures 683<br />

• WSFACTOR identifies two within-subjects factors whose levels distinguish the six dependent<br />

variables. X has three levels and Y has two. Thus, there are 3 × 2 =<br />

6 cells in the<br />

within-subjects design, corresponding to the six dependent variables.<br />

• Variable X1Y1 corresponds to levels 1,1 of the two within-subjects factors; variable X1Y2<br />

corresponds to levels 1,2; X2Y1 to levels 2,1; and so on up to X3Y2, which corresponds to<br />

levels 3,2. The first within-subjects factor named, X, varies most slowly, and the last withinsubjects<br />

factor named, Y, varies most rapidly on the list of dependent variables.<br />

• Because there is no WSDESIGN subcommand, the within-subjects design will include all<br />

main effects and interactions: X, Y, and X by Y.<br />

• Likewise, the between-subjects design includes all main effects and interactions<br />

(TREATMNT, GROUP, and TREATMNT by GROUP) plus the intercept.<br />

• In addition, a repeated measures analysis always includes interactions between the withinsubjects<br />

factors and the between-subjects factors. There are three such interactions for<br />

each of the three within-subjects effects.<br />

Example<br />

GLM SCORE1 SCORE2 SCORE3 BY GROUP<br />

/WSFACTOR=ROUND 3 DIFFERENCE<br />

/CONTRAST(GROUP)=DEVIATION<br />

/PRINT=PARAMETER TEST(LMATRIX).<br />

• This analysis has one between-subjects factor, GROUP, and one within-subjects factor,<br />

ROUND, with three levels that are represented by the three dependent variables.<br />

• The WSFACTOR subcommand also specifies difference contrasts for ROUND, the withinsubjects<br />

factor.<br />

• There is no WSDESIGN subcommand, so a default full factorial within-subjects design is<br />

assumed. This could also have been specified as WSDESIGN=ROUND, or simply<br />

WSDESIGN.<br />

• The CONTRAST subcommand specifies deviation contrasts for GROUP, the betweensubjects<br />

factor. This subcommand could have been omitted because deviation contrasts<br />

are the default.<br />

• PRINT requests the display of the parameter estimates for the model and the L matrix.<br />

• There is no DESIGN subcommand, so a default full factorial between-subjects design is<br />

assumed. This could also have been specified as DESIGN=GROUP, or simply DESIGN.<br />

WSDESIGN Subcommand<br />

WSDESIGN specifies the design for within-subjects factors. Its specifications are like those<br />

of the DESIGN subcommand, but it uses the within-subjects factors rather than the betweensubjects<br />

factors.<br />

• The default WSDESIGN is a full factorial design, which includes all main effects and all<br />

interactions for within-subjects factors. The default is in effect whenever a design is<br />

processed without a preceding WSDESIGN or when the preceding WSDESIGN subcommand<br />

has no specifications.<br />

• A WSDESIGN specification cannot include between-subjects factors or terms based on<br />

them, nor does it accept interval-level variables.<br />

• The keyword INTERCEPT is not allowed on WSDESIGN.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!