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Details of the OPTEX Procedure 
See OPTEX9 in the SAS/QC Sample Library 
In addition to finding optimal block designs, you can use the BLOCKS statement to find designs that are optimal with respect to more general covariate models. You can specify the data set containing the covariates with the DESIGN= option in the BLOCKS statement. Covariate models are specified in the same way as the treatment model.
The following example is based on an example in Harville (1974). Suppose you want a design for five qualitative treatments in 10 runs. The value of a covariate thought to be related to the response has been recorded for each of the experimental units. For instance, if the treatments are different types of animal feed, a typical covariate might be the initial weight of each animal. In the following, the data sets COV and TMT are created, containing the covariate values and the candidate treatment levels, respectively. Then the OPTEX procedure is invoked with a simple oneway model for the treatment effect and a quadratic model for the covariate effect.
data cov; input u @@@@; datalines; .46 .54 .58 .60 .73 .77 .82 .84 .89 .95 ; data tmt; do t = 1 to 5; output; end; proc optex data=tmt seed=17364 coding=orthcan; class t; model t; blocks design=cov; model u u*u; output out=tmtu; proc print data=tmtu; run;In this case, the CODING=ORTHCAN option in the PROC OPTEX statement has the same effect as CODING=ORTH, which is to produce orthogonal coding with respect to the candidates. Note that
The listing of the efficiency values for the 10 designs found is shown in Output 24.8.1. Note that the efficiencies are the same for all tries. A listing of the design is shown in Output 24.8.2.
Output 24.8.1: Optimal Treatment Efficiency Factors with a Quadratic Covariate Effect

data har; input t @@@@; datalines; 1 2 3 4 5 1 2 3 4 5 ; proc optex data=tmt coding=orthcan; class t; model t; generate initdesign=har method=sequential; blocks design=cov init=chain iter=0; model u u*u; run;The efficiency values for Harville's design are shown in Output 24.8.3. They are the same as for the design found by the OPTEX procedure. Output 24.8.3: Treatment Efficiency Factors for Harville's Design

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