The basic syntax for the IRCHART statement is as follows:
- IRCHART process*subgroup-variable ;
The general form of this syntax is as follows:
- IRCHART (processes)*subgroup-variable
<(block-variables ) >
- < =symbol-variable | ='character' >
< / options >;
You can use any number of IRCHART statements
in the SHEWHART procedure.
The components of the IRCHART statement are described as follows.
identify one or more processes to be analyzed.
The specification of process depends on
the input data set specified in the PROC SHEWHART
- If raw data are read from a DATA= data set, process
must be the name of the variable containing
the individual measurements.
For an example, see "Creating Individual Measurements and Moving Range Charts" .
- If individual measurements and moving ranges are read from
a HISTORY= data set,
process must be the name of the variable
containing the individual measurements as well as the prefix
of the variable containing the moving ranges in
the HISTORY= data set.
For an example, see "Saving Individual Measurements and Moving Ranges" .
- If individual measurements, moving ranges, and control
limits are read from a TABLE= data set,
process must be the value of the variable _VAR_ in
the TABLE= data set.
For an example, see "Saving Control Limits" .
A process is required. If you specify more than one process,
enclose the list in parentheses.
For example, the following statements request distinct
individual measurements and moving range charts for
WEIGHT, LENGTH, and WIDTH:
proc shewhart data=measures;
irchart (weight length width)*day;
is the variable that identifies subgroups in the data.
The subgroup-variable is required.
In the preceding IRCHART statement, DAY is the subgroup variable.
Note that each "subgroup" consists of a single observation.
For details, see "Subgroup Variables" .
are optional variables that group the data into blocks of
consecutive subgroups. The blocks are labeled in a legend,
and each block-variable provides one level of labels in
See "Displaying Stratification in Blocks of Observations" for an example.
is an optional variable whose levels (unique values)
determine the symbol marker or character used to plot the
individual measurements and moving ranges.
- If you produce a chart on a line printer, an `A' is
displayed for the points corresponding to the first level of
the symbol-variable, a `B' is displayed for the points
corresponding to the second level, and so on.
- If you produce a chart on a graphics device,
distinct symbol markers are displayed for points
corresponding to the various levels of the symbol-variable.
You can specify the symbol markers with SYMBOLn statements.
See "Displaying Stratification in Levels of a Classification Variable" for an example.
specifies a plotting character for charts produced on line printers.
For example, the following statements create charts using an
asterisk (*) to plot the points:
proc shewhart data=values;
- enhance the appearance of the charts, request
additional analyses, save results in data sets, and so on.
The "Summary of Options" section, which follows, lists all
options by function. Chapter 46, "Dictionary of Options,"
describes each option in detail.
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.