The basic syntax for the SCHART statement is as follows:
- SCHART process*subgroup-variable ;
The general form of this syntax is as follows:
- SCHART (processes)*subgroup-variable
<(block-variables ) >
- < =symbol-variable | ='character' >
< / options >;
You can use any number of SCHART statements in the SHEWHART procedure.
The components of the SCHART 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 s charts for
WEIGHT, LENGTH, and WIDTH:
proc shewhart data=measures;
schart (weight length width)*day;
is the variable that identifies subgroups in the data.
The subgroup-variable is required.
In the preceding SCHART 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
subgroup standard deviations.
- 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 s 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.