SPSS® 12.0 Command Syntax Reference

1218 PLUM
• Covariates can be connected, but not nested, using the keyword BY or the asterisk (*)
operator. For example, X*X is the product of X and itself. This is equivalent to a covariate
whose values are the square of those of X. On the contrary, X(Y) is invalid.
• Factor and covariate effects can be connected in many ways. No effects can be nested
within a covariate effect. Suppose A and B are factors, and X and Y are covariates.
Examples of valid combination of factor and covariate effects are A*X, A*B*X, X(A),
X(A*B), X*A(B), X*Y(A*B), and A*B*X*Y.
TEST Subcommand
The TEST subcommand allows you to customize your hypothesis tests by directly specifying
null hypotheses as linear combinations of parameters.
• TEST is offered only through syntax.
• Multiple TEST subcommands are allowed. Each is handled independently.
• The basic format of the TEST subcommand is an optional list of values enclosed in a pair
of parentheses, an optional label in quotes, an effect name or the keyword ALL, and a list
of values.
• To specify the coefficient for the intercept, use the keyword INTERCEPT. The number
of values after INTERCEPT must be equal to the number of response categories minus 1.
• When multiple linear combinations are specified within the same TEST subcommand, a
semicolon terminates each linear combination, except the last one.
• The linear combinations are separately tested for each category of the dependent variable
and then simultaneously tested for all the categories.
• If specified, the value list that immediately follows the subcommand name is the constant
that the linear combinations are equated to under the null hypotheses. If this value list is
omitted, the constants are assumed to be all zeros.
• The optional label is a string with a maximum length of 255 characters (or 127 doublebyte
characters). Only one label per TEST subcommand can be specified.
• Only valid effects appearing or implied on the LOCATION or the SCALE subcommands
can be specified in a linear combination. If an effect appears in both subcommands, then
enter the effect only once on the TEST subcommand.
• To specify coefficient for the intercept, use the keyword INTERCEPT. Only one value is
expected to follow INTERCEPT.
• The number of values following an effect name must equal the number of parameters
(including the redundant ones) corresponding to that effect. For example, if the effect
A*B takes up six parameters, then exactly six values must follow A*B.
• A number can be specified as a fraction with a positive denominator. For example, 1/3 or
-1/3 are valid, but 1/-3 is invalid.
• When ALL is specified, only a list of values can follow. The number of values must equal
the combined number of LOCATION and SCALE parameters (including the redundant
ones).
• Effects appearing or implied on the LOCATION or the SCALE subcommands but not
specified on the TEST are assumed to take the value 0 for all their parameters.