Represents a factor by factorial combinations of a set of factors (R.W. Payne).
||Factor whose levels are to be represented by the factorial combinations of the
||Factors formed to represent
||Levels of the
FACDIVIDE allows a set of factors to be formed with a set of levels for every level of another factor. (It is thus provides the opposite operation to the procedure
FACPRODUCT, which forms a factor with a level for every combination of the levels of a set of factors.)
FACDIVIDE may be useful, for example, if a design for a single factor, such as a Latin square, is to be used to study several factors and their interactions: e.g. a 12 by 12 Latin square could be used to study the main effects and interaction of factors A and B with 3 and 4 levels respectively.
The original factor is specified by the
OLDFACTOR option, and the
LEVELS parameters specify the new factors and their levels. So, to represent the 12-level factor
Treat by factors
B as above, would require
FACDIVIDE [OLDFACTOR=Treat] NEWFACTOR=A,B; LEVELS=3,4
As in the
FACTOR directive, the
LEVELS parameter can be set to a scalar if the new factor is to have the standard levels 1, 2 and so on, or to a variate if you want to specify some other levels.
GENERATE to form a set of mapping vectors containing the levels of the new factors, in standard order. It then uses these in the
NEWLEVELS function to calculate the levels of the new factors.
OLDFACTOR is restricted, the levels will be formed only for the units not excluded by the restriction.
CAPTION 'FACDIVIDE example'; STYLE=meta FACTOR [LEVELS=12; VALUES=2,10,5,6,11,3,8,1,9,4,12,7] Factor12 FACDIVIDE [OLDFACTOR=Factor12] Factor3,Factor4; LEVELS=3,4 PRINT Factor12,Factor3,Factor4 " sort the levels to see how they have been allocated " SORT Factor12,Factor3,Factor4 PRINT Factor12,Factor3,Factor4