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The FACTEX Procedure

Summary of Designs

Table 7.5 summarizes basic design types that you can construct with the FACTEX procedure by providing example code for each type.

Table 7.5 Basic Designs Constructed by the FACTEX Procedure

Design Type

Example Statements

A full factorial design in three factors, each at two levels coded as and .

proc factex;
   factors Pressure Temperature Time;
   examine design;
run;

A full factorial design in three factors, each at three levels coded as , , and .

proc factex;
   factors Pressure Temperature Time / nlev= 3;
   examine design;
run;

A full factorial design in three factors, each at two levels. The entire design is replicated twice, and the design with recoded factor levels is saved in a SAS data set.

proc factex;
   factors Pressure Temperature Time;
   output out= SavedDesign designrep= 2
          Pressure cvals=('low' 'high')
          Temperature nvals=(200 300)
          Time nvals=(10 20);
run;

A full factorial design in three factors, each at two levels coded as and . Each run in the design is replicated three times, and the replicated design is randomized and saved in a SAS data set.

proc factex;
   factors Pressure Temperature Time;
   output out= SavedDesign
          pointrep= 3 randomize;
run;

A full factorial design in three control factors, each at two levels coded as and . A noise factor design (outer array) read from a SAS data set is replicated for each run in the control factor design (inner array), and the product design is saved in a SAS data set.

proc factex;
factors+ Pressure Temperature Time;
   output out     =+ SavedDesign
          pointrep=+ OutArray;
run;

A full factorial blocked design in three factors, each at two levels coded as and . The design is arranged in two blocks and saved in a SAS data set. By default, the block variable is named BLOCK and the two block levels are numbered 1 and 2.

proc factex;
   factors Pressure Temperature Time;
   blocks nblocks= 2;
   output out= SavedDesign;
run;

A full factorial blocked design in three factors, each at two levels coded as and . Each block contains four runs; the block variable is renamed and the block levels of character type are recoded. The design is saved in a SAS data set.

proc factex;
   factors Pressure Temperature Time;
   blocks size= 4;
   output out= SavedDesign
          blockname= Machine cvals=('A' 'B' );
run;

A fractional factorial design of resolution 4 in four factors, each at two levels coded as and . The size of the design is eight runs.

proc factex;
   factors Pressure Temperature Time Catalyst;
   size design= 8;
   model resolution= 4;
   examine design;
run;

A one-half fraction of a factorial design in four factors, each at two levels coded as and . The design is of maximum resolution. The design points, the alias structure, and the confounding rules are listed.

proc factex;
   factors Pressure Temperature Time Catalyst;
   size fraction= 2;
   model resolution=maximum;
   examine design aliasing confounding;
run;

A one-quarter fraction of a factorial design in six factors, each at two levels coded as and . Main effects are estimated, and some two-factor interactions are considered nonnegligible. The design is saved in a SAS data set.

proc factex;
   factors x1-x6;
   size fraction= 4;
   model estimate=( x1 x2 x3 x4 x5 x6 )
         nonneg  =( x1*x5 x1*x6 x5*x6 );
   output out    = SavedDesign;
run;
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