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The PLAN Procedure

Three Replications with Four Factors

Suppose you want to determine if the order in which four drugs are given affects the response of a subject. If you have only three subjects to test, you can use the following statements to design the experiment.

   proc plan seed=27371;
      factors Replicate=3 ordered Drug=4;
   run;

These statements produce a design with three replicates of the four levels of the factor Drug arranged in random order. The three levels of Replicate are arranged in order, as shown in Figure 50.1

The PLAN Procedure

Factor Select Levels Order
Replicate 3 3 Ordered
Drug 4 4 Random

Replicate Drug
1 3 2 4 1
2 1 2 4 3
3 4 1 2 3

Figure 50.1: Three Replications and Four Factors

You may also want to apply one of four different treatments to each cell of this plan (for example, applying different amounts of each drug). The following statements create the output shown in Figure 50.2

      factors Replicate=3 ordered Drug=4;
      treatments Treatment=4;
   run;

The PLAN Procedure

Plot Factors
Factor Select Levels Order
Replicate 3 3 Ordered
Drug 4 4 Random

Treatment Factors
Factor Select Levels Order
Treatment 4 4 Random

Replicate Drug Treatment
1 3 1 2 4 2 1 3 4
2 4 3 2 1 4 1 2 3
3 3 2 4 1 1 4 2 3

Figure 50.2: Using the TREATMENTS Statement

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