Specifying Factor Structures |
By appropriately combining features of the PLAN procedure, you can construct an extensive set of designs. The basic tools are the factor-selections, which are used in the FACTORS and TREATMENTS statements. Table 67.1 summarizes how the procedure interprets various factor-selections (assuming that the ORDERED option is not specified in the PROC PLAN statement).
Form of |
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Request |
Interpretation |
Example |
Results |
name= |
produce a random permutation of the integers |
t=15 |
lists a random ordering of the numbers |
name= |
cyclically permute the integers |
t=5 cyclic |
selects the integers 1 to 5. On the next iteration, selects 2,3,4,5,1; then 3,4,5,1,2; and so on. |
name= of |
choose a random sample of integers (without replacement) from the set of integers |
t=5 of 15 |
lists a random selection of 5 numbers from 1 to 15. First, the procedure selects 5 numbers and then arranges them in random order. |
name= of |
has the same effect as name= ordered |
t=5 of 15 |
lists the integers 1 to 5 in increasing order (same as t=5 ordered) |
name= of |
permute of the integers |
t=5 of 30 |
selects the integers 1 to 5. On the next iteration, selects 2,3,4,5,6; then 3,4,5,6,7; and so on. The 30th iteration produces 30,1,2,3,4; the 31st iteration produces 1,2,3,4,5; and so on. |
name= |
produce a list of all permutations of integers |
t=5 perm |
lists the integers 1,2,3,4,5 on the first iteration; on the second lists 1,2,3,5,4; on the 119th iteration lists 5,4,3,1,2; and on the last (120th) lists 5,4,3,2,1. |
name= of |
choose combinations of integers from integers |
t=3 of 5 |
lists all combinations of 5 choose 3 integers. The first iteration is 1,2,3; the second is 1,2,4; the third is 1,2,5; and so on until the last iteration 3,4,5. |
name= of |
permute of the integers, starting with the values specified in the initial-block |
t=4 of 30 |
selects the integers 2,10,15,18. On the next iteration, selects 3,11,16,19; then 4,12,17,20; and so on. The thirteenth iteration is 14,22,27,30; the fourteenth iteration is 15,23,28,1; and so on. |
name= of |
permute of the integers. Start with the values specified in the initial-block, then add the increment to each value. |
t=4 of 30 |
selects the integers 2,10,15,18. On the next iteration, selects 4,12,17,20; then 6,14,19,22; and so on. The wrap occurs at the eighth iteration. The eighth iteration is 16,24,29,2; and so on. |
In Table 67.1, in order for more than one iteration to appear in the plan, another name=j factor selection (with ) must precede the example factor selection. For example, the following statements produce six of the iterations described in the last entry of Table 67.1.
proc plan; factors c=6 ordered t=4 of 30 cyclic (2 10 15 18) 2; run;
The following statements create a randomized complete block design and output the design to a data set.
proc plan ordered; factors blocks=3 cell=5; treatments t=5 random; output out=rcdb; run;