IRCHART Statement: SHEWHART Procedure

Reading Individual Measurements and Moving Ranges

[See SHWIR1 in the SAS/QC Sample Library]In some applications, both individual measurements and moving ranges may be provided. You can read this type of data set by specifying it with the HISTORY= option in the PROC SHEWHART statement. For example, the following statements read the data set Jetinfo (see Figure 15.29) and create the charts shown in Figure 15.30:

symbol h = .8;
title 'Individual Measurements and Moving Range Charts';
proc shewhart history=Jetinfo;
   irchart Diam*Engine;
run;

Figure 15.30 Charts Produced from Summary Data Set Jetinfo

A HISTORY= data set used with the IRCHART statement must contain the following variables:

• subgroup variable

• individual measurements variable

• moving range variable

Furthermore, the name of the moving range variable must begin with the process name specified in the IRCHART statement and end with the special suffix character R. If the name does not follow this convention, you can use the RENAME option in the PROC SHEWHART statement to rename this variable for the duration of the procedure step (see Creating Charts for Means and Ranges from Summary Data). For more information, see HISTORY= Data Set.