SAS/STAT 9.2 User's Guide: The MIXED Procedure (Book Excerpt)

3896 ✦ Chapter 56: The MIXED Procedure
Figure 56.14 Type 3 Tests of Fixed Effects
Type 3 Tests of Fixed Effects
Num Den
Effect DF DF F Value Pr > F
Gender 1 3 7.95 0.0667
An additional benefit of the random effects analysis is that it enables you to make inferences about
gender that apply to an entire population of families, whereas the inferences about gender from the
analysis where Family and Family*Gender are fixed effects apply only to the particular families in the
data set.
PROC MIXED thus offers you the ability to model correlation directly and to make inferences about
fixed effects that apply to entire populations of random effects.
Syntax: MIXED Procedure
The following statements are available in PROC MIXED.
PROC MIXED < options > ;
BY variables ;
CLASS variables ;
ID variables ;
MODEL dependent = < fixed-effects > < / options > ;
RANDOM random-effects < / options > ;
REPEATED < repeated-effect >< / options > ;
PARMS (value-list) . . . < / options > ;
PRIOR < distribution >< / options > ;
CONTRAST ’label’ < fixed-effect values . . . >
< | random-effect values . . . >, . . . < / options > ;
ESTIMATE ’label’ < fixed-effect values . . . >
< | random-effect values . . . >< / options > ;
LSMEANS fixed-effects < / options > ;
WEIGHT variable ;
Items within angle brackets ( < > ) are optional. The CONTRAST, ESTIMATE, LSMEANS, and
RANDOM statements can appear multiple times; all other statements can appear only once.
The PROC MIXED and MODEL statements are required, and the MODEL statement must appear
after the CLASS statement if a CLASS statement is included. The CONTRAST, ESTIMATE,
LSMEANS, RANDOM, and REPEATED statements must follow the MODEL statement. The
CONTRAST and ESTIMATE statements must also follow any RANDOM statements.
Table 56.1 summarizes the basic functions and important options of each PROC MIXED statement.