XSCHART Statement: SHEWHART Procedure

Note: See Mean and Standard Deviation Charts Examples in the SAS/QC Sample Library.

In the previous example, the OUTLIMITS= data set Turblim saved control limits computed from the measurements in Turbine. This example shows how these limits can be applied to new data. The following statements create and s charts for new measurements in a data set named Turbine2 (not listed here) using the control limits in Turblim:

ods graphics on;
title 'Mean and Standard Deviation Charts for Power Output';
proc shewhart data=Turbine2 limits=Turblim;
   xschart KWatts*Day / odstitle = title;
run;

The ODS GRAPHICS ON statement specified before the PROC SHEWHART statement enables ODS Graphics, so the and s charts are created by using ODS Graphics instead of traditional graphics. The charts are shown in Figure 17.120.

The LIMITS= option in the PROC SHEWHART statement specifies the data set containing preestablished control limit information. By default, this information is read from the first observation in the LIMITS= data set for which

The means and standard deviations lie within the control limits, indicating that the heating process is still in statistical control.

In this example, the LIMITS= data set was created in a previous run of the SHEWHART procedure. You can also create a LIMITS= data set with the DATA step. See LIMITS= Data Set for details concerning the variables that you must provide.