Example 15.5: Randomized Complete Block Design

Details of the FACTEX Procedure

Example 15.5: Randomized Complete Block Design

See FACTEX11 in the SAS/QC Sample Library

In a randomized complete block design (RCBD), each level of a "treatment" appears once in each block, and each block contains all the treatments. The order of treatments is randomized separately for each block. You can create RCBDs with the FACTEX procedure.

Suppose you want to construct an RCBD with six treatments in four blocks. To test each treatment once in each block, you need 24 experimental units. The following statements construct the randomized complete block design shown in Output 15.5.1:

   proc factex;
      factors block / nlev=4;      
      output out=blocks     
             block nvals=(1 2 3 4);
   run;
      factors trt / nlev=6;        
      output out=rcbd            
             designrep=blocks      
             randomize (101)         
             trt cvals=('A' 'B' 'C'
                        'D' 'E' 'F');
   run;

   proc print data=rcbd;
   run;

Note that the order of the runs within each block is randomized and that the blocks (1, 2, 3, and 4) are in a random order.

Output 15.5.1: A Randomized Complete Block Design

Obs	blocks	trt
1	1	B
2	1	A
3	1	D
4	1	E
5	1	F
6	1	C
7	4	B
8	4	D
9	4	C
10	4	A
11	4	E
12	4	F
13	2	B
14	2	C
15	2	F
16	2	E
17	2	D
18	2	A
19	3	C
20	3	A
21	3	B
22	3	E
23	3	F
24	3	D

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