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SPSS® 12.0 Command Syntax Reference

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886 MANOVA: Repeated Measures<br />

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

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

6 cells<br />

in the 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<br />

within-subjects 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.<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 />

CONTRAST for WSFACTORS<br />

The levels of a within-subjects factor are represented by different dependent variables.<br />

Therefore, contrasts between levels of such a factor compare these dependent variables.<br />

Specifying the type of contrast amounts to specifying a transformation to be performed on<br />

the dependent variables.<br />

• An orthonormal transformation is automatically performed on the dependent variables in<br />

a repeated measures analysis.<br />

• To specify the type of orthonormal transformation, use the CONTRAST subcommand for<br />

the within-subjects factors.<br />

• Regardless of the contrast type you specify, the transformation matrix is orthonormalized<br />

before use.<br />

• If you do not specify a contrast type for within-subjects factors, the default contrast type<br />

is orthogonal POLYNOMIAL. Intrinsically orthogonal contrast types are recommended<br />

for within-subjects factors if you wish to examine each degree-of-freedom test. Other<br />

orthogonal contrast types are DIFFERENCE and HELMERT. MULTIV and AVERF tests are<br />

identical, no matter what contrast was specified.<br />

• To perform non-orthogonal contrasts, you must use the TRANSFORM subcommand instead<br />

of CONTRAST. The TRANSFORM subcommand is discussed in MANOVA: Multivariate.<br />

• When you implicitly request a transformation of the dependent variables with CONTRAST<br />

for within-subjects factors, the same transformation is applied to any covariates in the<br />

analysis. The number of covariates must be an integer multiple of the number of dependent<br />

variables.<br />

• You can display the transpose of the transformation matrix generated by your withinsubjects<br />

contrast using the keyword TRANSFORM on the PRINT subcommand.

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