Example 15.1: Completely Randomized Design

Details of the FACTEX Procedure

Example 15.1: Completely Randomized Design

See FACTEX8 in the SAS/QC Sample Library

An experimenter wants to study the effect of cutting speed (SPEED) on the surface finish of a component. He considers testing the components at five levels of cutting speed (100, 125, 150, 175, and 200) and decides to test five components at each level.

The design used is a single-factor completely randomized design with five levels and 25 runs. The following statements generate the required design:

   proc factex;
      factors speed / nlev=5;
      size design=25;
      output out=surfexpt randomize        /* Randomly assign run order */
         speed nvals=(100 125 150 175 200);
   run;

   proc print data=surfexpt;
   run;

The design saved in the data set SURFEXPT is displayed in Output 15.1.1.

Output 15.1.1: A Completely Randomized Design

Obs	speed
1	150
2	200
3	150
4	125
5	125
6	175
7	200
8	125
9	100
10	175
11	100
12	100
13	100
14	150
15	125
16	200
17	150
18	150
19	175
20	100
21	175
22	200
23	125
24	175
25	200

If you are working through this example on your computer, you might find a different run order in your output. This is due to the difference in the seed value of the random number generator. You can specify a seed value with the RANDOMIZE option. For syntax, see "Randomize Design" .

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