Breadwrapper Stock: Response-Surface Study

 /****************************************************************/
 /*              S A S   S A M P L E   L I B R A R Y             */
 /*                                                              */
 /*    NAME: ADXEG4                                              */
 /*   TITLE: Breadwrapper Stock: Response-Surface Study          */
 /* PRODUCT: QC                                                  */
 /*  SYSTEM: ALL                                                 */
 /*    KEYS: Design of Experiments,Factorial Designs             */
 /*   PROCS:                                                     */
 /*    DATA:                                                     */
 /*     REF: Myers, R.H. (1976).  Response Surface Methodology.  */
 /*               pp. 78-84.                                     */
 /*    MISC: ADX Macros are stored in the AUTOCALL library       */
 /*                                                              */
 /*                                                              */
 /* Myers (1976) uses a central composite design to test the seal*/
 /* strength in grams per inch of a breadwrapper stock.  The     */
 /* three factors that are examined are,                         */
 /*                                                              */
 /*      * the sealing temperature (STMP),                       */
 /*      * the cooling temperature (CTMP), and                   */
 /*      * the percentage of the polyethylene additive (POLY)    */
 /*               that is used.                                  */
 /*                                                              */
 /****************************************************************/




 /*--------------------------------------------------------------*/
 /*  EXAMPLE 4:  A CENTRAL COMPOSITE DESIGN FOR A BREADWRAPPER   */
 /*              STUDY.                                          */
 /*              SOURCE:  MYERS (1976).                          */
 /*--------------------------------------------------------------*/

 /*
 /  For this example, we need only the central composite design
 /  macros:
 /  if we haven't already included them, we do so now.
 /---------------------------------------------------------------*/
 %adxgen;
 %adxff;
 %adxcc;
 %adxinit                        /* Initialize ADX environment.  */

 /*
 /  First, find out which designs are available for the three
 /  treatment factors.
 /---------------------------------------------------------------*/
 %adxpcc(3)

 /*
 /  Myers chooses an 8-run design having 6 center points and the
 /  axial point value of 1.6818.  NOTE:  Although 9 center points
 /  are required to achieve an orthogonal design, you may specify
 /  only 6 center points.
 /---------------------------------------------------------------*/
 %adxccd(bread,3,8,6,1.6818)

 /*
 /  Decode the data.
 /---------------------------------------------------------------*/
 %adxdcode(bread,t1 stmp 225 285 /t2 ctmp 46 64 /t3 poly 0.5 1.7)

 /*
 /  Normally we would also make up a randomized data collection
 /  form to be submitted to the experimenter using the command
 /                     %adxrprt(bread,sealstr)
 /  Assuming that this was done and that the data has been
 /  collected, the results, which can be found in Myers (1976),
 /  page 79, are then added to this data set.
 /---------------------------------------------------------------*/
 data bread;
    set bread;
    input @@ sealstr;
    cards;
  6.6  9.2  7.9 10.4  6.9  6.8  6.1  7.3 10.1  9.9
 12.2  9.7  9.7  9.6  5.0  9.8  6.3  6.9  8.6  4.0
 ;
 run;

 /*
 /  Analyze this data using PROC RSREG.
 /---------------------------------------------------------------*/
 proc rsreg;
    model sealstr = stmp ctmp poly;
 run;







 /*--------------------------------------------------------------*/
 /*                                                              */
 /* We can conclude from the output that the significant effects */
 /* come from the following variables:  the main effects of the  */
 /* sealing temperature and the polyethylene additive, as well   */
 /* as all three of the quadratic variables.  The stationary     */
 /* point, which is a maximum, is given along with the estimated */
 /* response at this point.                                      */
 /*                                                              */
 /*--------------------------------------------------------------*/