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If you have specified analysis which has less ways than the number
of grouping variables given in GROUPING then the outermost grouping
variables will be combined into one new grouping variable. This
feature is useful, e.g. in a two-way analysis if you have decided
that the interaction of the two factors on the dependent variable
is significant:
    ANOVA IEADATA,25
    DEPENDENT=Knowldge  GROUPING=Attitude,Sex
    Attitude=1,2,3  Sex=1,2  METHOD=Tukey(s)
The six means of the combined variable A*S will be examined by
the Tukey-Kramer method. The combined variable will be named
by the initials of the original grouping variables.
     A = More on ANOVA operatiuons