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IRCHART Statement |
By default, the SHEWHART procedure reads all of the observations in a DATA= data set. However, if the DATA= data set includes the variable _PHASE_, you can read selected groups of observations (referred to as phases) by specifying the READPHASES= option in the IRCHART statement (for an example, see "Displaying Stratification in Phases" ).
For an example of a DATA= data set, see "Creating Individual Measurements and Moving Range Charts" .
proc shewhart data=info limits=conlims; irchart weight*id; run;
The LIMITS= data set can be an OUTLIMITS= data set that was created in a previous run of the SHEWHART procedure. Such data sets always contain the variables required for a LIMITS= data set; see Table 34.22. The LIMITS= data set can also be created directly using a DATA step.
When you create a LIMITS= data set, you must provide
one of the following:
In addition, note the following:
For an example, see "Reading Preestablished Control Limits" .
A HISTORY= data set used with the IRCHART statement
must contain the following:
The name of the individual measurements variable must be
the process specified in the IRCHART statement.
The name of the moving range variable must be the prefix
process concatenated with the special suffix character R.
For example, consider the following statements:
proc shewhart history=summary; irchart (weight yldstren)*id; run;
The data set SUMMARY must include the variables ID, WEIGHT, WEIGHTR, YLDSTREN, and YLDSRENR.
Note that if you specify a process name that contains eight characters, the name of the moving range variable must be formed from the first four characters and the last three characters of the process name, suffixed with R.
Other variables that can be read from a HISTORY= data set include
By default, the SHEWHART procedure reads all of the observations in a HISTORY= data set. However, if the data set includes the variable _PHASE_, you can read selected groups of observations (referred to as phases) by specifying the READPHASES= option (see "Displaying Stratification in Phases" for an example).
For an example of a HISTORY= data set, see "Reading Individual Measurements and Moving Ranges" .
The following table lists the variables required in a TABLE= data set used with the IRCHART statement:
Table 34.25: Variables Required in a TABLE= Data SetVariable | Description |
_LCLI_ | lower control limit for individual measurements |
_LCLR_ | lower control limit for moving range |
_LIMITN_ | number of consecutive measurements used to calculate moving ranges |
_MEAN_ | process mean |
_R_ | average moving range |
subgroup-variable | values of the subgroup-variable |
_SUBI_ | individual measurements |
_SUBR_ | moving ranges |
_UCLI_ | upper control limit for individual measurements |
_UCLR_ | upper control limit for moving range |
Other variables that can be read from a TABLE= data set include
For an example of a TABLE= data set, see "Saving Control Limits" .
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