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The SHEWHART Procedure

Saving Summary Statistics

[See SHWXR1 in the SAS/QC Sample Library]In this example, the XRCHART statement is used to create a summary data set that can be read later by the SHEWHART procedure (as in the preceding example). The following statements read measurements from the data set Wafers and create a summary data set named Waferhist:

proc shewhart data=Wafers;
   xrchart Diameter*Batch / outhistory = Waferhist
                            nochart;
run;

The OUTHISTORY= option names the output data set, and the NOCHART option suppresses the display of charts. Figure 13.37.6 contains a partial listing of Waferhist.

Output 13.37.6 Partial Listing of the Summary Data Set Waferhist
Summary Data Set for Wafer Diameters

Batch DiameterX DiameterR DiameterN
1 34.992 0.02 5
2 34.994 0.03 5
3 34.998 0.01 5
4 34.998 0.02 5
5 34.992 0.02 5

There are four variables in the data set Waferhist:

  • Batch contains the subgroup index.

  • DiameterX contains the subgroup means.

  • DiameterR contains the subgroup ranges.

  • DiameterN contains the subgroup sample sizes.

Note that the summary statistic variables are named by adding the suffix characters X, R, and N to the process Diameter specified in the XRCHART statement. In other words, the variable naming convention for OUTHISTORY= data sets is the same as that for HISTORY= data sets.

For more information, see OUTHISTORY= Data Set.

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