Help System (web edition)

If in the analysis of variance the numbers of observations in the cells
defined by the grouping variables are equal then also random effects
mixed models are possible. Those grouping variables, whose effects
on the dependent variable are regarded as random, are given by the
parameter RANDOM, e.g.

    ANOVA IEADATA,30
    DEPENDENT=WEIGHT
    GROUPING=MICE,FOOD
    MICE=1(1)4   FOOD=1,2,3
    INCLUDED=MF  RANDOM=MICE  METHOD=TWOWAY

where the main effect of MICE is regarded as random and  FOOD as fixed.
Their interaction is regarded as random.

Further information:
    1 = More on definitions of the grouping structure 
    2 = More on analysis of variance for multiple factors 
    A = More on ANOVA operations