The SHEWHART Procedure

Syntax: INSET and INSET2 Statements

Subsections:

The syntax for the INSET and INSET2 statements is as follows:

You can use any number of INSET and INSET2 statements in the SHEWHART procedure. However, when ODS Graphics is enabled, at most two insets are displayed inside the primary and secondary plot areas, and at most two are displayed in the chart margins. Each INSET or INSET2 statement produces a separate inset and must follow one of the chart statements. The inset appears on every panel (page) produced by the last chart statement preceding it. The statistics are displayed in the order in which they are specified. The following statements produce a boxplot with two insets and an $\bar{X}$ and R chart with one inset in the $\bar{X}$ chart and one in the R chart. 

proc shewhart data=Wafers;
   boxchart Diameter * Batch / lsl=34.9 target=35 usl=35.1;
      inset lsl target usl;
      inset cp cpk cpm;
   xrchart Diameter * Batch;
      inset nmin nmax nout;
      inset2 nlow2 nhigh2;
run;

The statistics displayed in an inset are computed for a specific process variable using observations for the current BY group. For example, in the following statements, there are two process variables (Weight and Diameter) and a BY variable (Location). If there are three different locations (levels of Location), then a total of six $\bar{X}$ charts are produced. The statistics in each inset are computed for a particular variable and location. The labels in the inset are the same for each $\bar{X}$ chart. 

proc shewhart data=Axles;
   by Location;
   xchart (Weight Diameter) * Batch / tests=1 to 8;
   inset ntests 1 to 8;
run;

The components of the INSET and INSET2 statements are described as follows.

keyword-list

can include any of the keywords listed in Summary of INSET Keywords. Some keywords, such as NTESTS and DATA=, require operands specified immediately after the keyword. Also, some inset statistics are available only if you request chart statements and options for which those statistics are calculated. For example,

  • the NHIGH2, NLOW2, NTESTS2, LCL2 and UCL2 keywords are available only when a secondary chart is produced with the IRCHART, MRCHART, XRCHART or XSCHART statements.

  • the NTESTS keyword requires the TESTS= option;

  • the NTESTS2 keyword requires the TESTS2= option;

  • the capability index keywords such as CPK all require one or more of the LSL=, USL= and TARGET= options.

By default, inset statistics are identified with appropriate labels, and numeric values are printed using appropriate formats. However, you can provide customized labels and formats. You provide the customized label by specifying the keyword for that statistic followed by an equal sign (=) and the label in quotes. Labels can have up to 24 characters. You provide the numeric format in parentheses after the keyword. Note that if you specify both a label and a format for a statistic, the label must appear before the format. For an example, see Formatting Values and Customizing Labels.

options

appear after the slash (/) and control the appearance of the inset. For example, the following INSET statement uses two appearance options (POSITION= and CTEXT=): 

inset n nmin nmax / position=ne ctext=yellow;

The POSITION= option determines the location of the inset, and the CTEXT= option specifies the color of the text of the inset.

See Summary of Options for a list of all available options, and Dictionary of Options for detailed descriptions. Note the difference between keywords and options; keywords specify the information to be displayed in an inset, whereas options control the appearance of the inset.