XRCHART Statement: SHEWHART Procedure

Saving Summary Statistics

Note: See Mean and Range (X-Bar and R) Charts 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 17.109 contains a partial listing of Waferhist.

Figure 17.109: 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.