The basic syntax for the XCHART statement is as follows:
- XCHART process*subgroup-variable ;
The general form of this syntax is as follows:
- XCHART (processes)*subgroup-variable
<(block-variables ) >
- < =symbol-variable | ='character' >
< / options >;
You can use any number of XCHART statements in the SHEWHART procedure.
The components of the XCHART 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 statement.
A process is required. If you specify more than one process,
enclose the list in parentheses. For example, the
following statements request distinct charts for
WEIGHT, LENGTH, and WIDTH:
proc shewhart data=measures;
xchart (weight length width)*day;
is the variable
that identifies subgroups in the data.
The subgroup-variable is required.
In the preceding XCHART statement, DAY is the subgroup variable.
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 the legend.
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 means.
- 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 an chart using an asterisk (*) to plot the points:
proc shewhart data=values;
- enhance the appearance of the chart, 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.