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SPSS® 12.0 Command Syntax Reference

SPSS® 12.0 Command Syntax Reference

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660 GLM: Univariate<br />

(*) or the keyword BY to specify crossed factors. A factor cannot occur in a<br />

single factor combination more than once.<br />

The order of factors in a factor combination is important, and there is no<br />

restriction on the order of factors. If a single factor is specified after the<br />

PROFILE keyword, a line plot of estimated means at each level of the factor<br />

is produced. If a two-way crossed factor combination is specified, the output<br />

includes a multiple-line plot of estimated means at each level of the first specified<br />

factor, with a separate line drawn for each level of the second specified<br />

factor. If a three-way crossed factor combination is specified, the output<br />

includes multiple-line plots of estimated means at each level of the first<br />

specified factor, with separate lines for each level of the second factor, and<br />

separate plots for each level of the third factor.<br />

Example<br />

GLM DEP BY A B<br />

/PLOT = SPREADLEVEL PROFILE(A A*B A*B*C)<br />

/DESIGN.<br />

Assume each of the factors A, B, and C has three levels.<br />

• Spread-versus-level plots are produced showing observed cell means versus standard<br />

deviations and observed cell means versus variances.<br />

• Five profile plots are produced. For factor A, a line plot of estimated means at each level<br />

of A is produced (one plot). For the two-way crossed factor combination A*B, a multipleline<br />

plot of estimated means at each level of A, with a separate line for each level of B, is<br />

produced (one plot). For the three-way crossed factor combination A*B*C, a multiple-line<br />

plot of estimated means at each level of A, with a separate line for each level of B, is<br />

produced for each of the three levels of C (three plots).<br />

TEST Subcommand<br />

The TEST subcommand allows you to test a hypothesis term against a specified error term.<br />

• TEST is valid only for univariate analyses. Multiple TEST subcommands are allowed,<br />

each executed independently.<br />

• You must specify both the hypothesis term and the error term. There is no default.<br />

• The hypothesis term is specified before the keyword VS. It must be a valid effect specified<br />

or implied on the DESIGN subcommand.<br />

• The error term is specified after the keyword VS. You can specify either a linear combination<br />

or a value. The linear combination of effects takes the general form:<br />

coefficient*effect +/– coefficient*effect ...<br />

• All effects in the linear combination must be specified or implied on the DESIGN subcommand.<br />

Effects specified or implied on DESIGN but not listed after VS are assumed to have<br />

a coefficient of 0.<br />

• Duplicate effects are allowed. GLM adds coefficients associated with the same effect<br />

before performing the test. For example, the linear combination 5*A–0.9*B–A will be<br />

combined to 4*A–0.9B.

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