The SHEWHART Procedure |
Learning to Use the SHEWHART Procedure |
Although the SHEWHART procedure provides a large number of options, you can use the procedure to create a basic Shewhart chart with as few as two SAS statements:
the PROC SHEWHART statement, which starts the procedure and specifies the input SAS data set
a chart statement, which specifies the type of Shewhart chart you want to create and the variables in the input data set that you want to analyze
For example, you can use the following statements to create and charts with limits for measurements read from a SAS data set named Drums:
proc shewhart data=Drums; xrchart Flangewidth * Hour; run;
The keyword XRCHART in the chart statement specifies that and charts are to be created. The following SAS variables are specified in the XRCHART statement:
A SAS variable (Flangewidth), whose values are the process measurements, is specified before the asterisk. This variable is referred to as the process.
A SAS variable (Hour), whose values classify the measurements into subgroups, is specified after the asterisk. This variable is referred to as a subgroup-variable.
The same form of specification is used with other chart statements to create different types of Shewhart charts. The following table lists the 13 chart statements that are available with the SHEWHART procedure:
Statement |
Chart(s) Displayed |
"Getting Started" Section |
---|---|---|
BOXCHART |
box chart with optional trend chart |
|
CCHART |
chart |
|
IRCHART |
individual and moving range charts |
|
MCHART |
median chart with optional trend chart |
|
MRCHART |
median and charts |
|
NPCHART |
chart |
|
PCHART |
chart |
|
RCHART |
chart |
|
SCHART |
chart |
|
UCHART |
chart |
|
XCHART |
chart with optional trend chart |
|
XRCHART |
and charts |
|
XSCHART |
and charts |
If you are using the SHEWHART procedure for the first time, you should do the following:
Read the "Getting Started" subsection in the section for the chart statement you need to create your chart. Table 13.1 provides links to these sections.
Once you have learned to use a particular chart statement, you will find it straightforward to use the remaining chart statements since their syntax is nearly the same. A separate, self-contained section is provided for each chart statement.
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