Chapter Contents |
Previous |
Next |
XCHART Statement |
Variable | Description |
_ALPHA_ | probability () of exceeding limits |
_CP_ | capability index C_{p} |
_CPK_ | capability index C_{pk} |
_CPL_ | capability index CPL |
_CPM_ | capability index C_{pm} |
_CPU_ | capability index CPU |
_INDEX_ | optional identifier for the control limits specified with the OUTINDEX= option |
_LCLR_ | lower control limit for subgroup range |
_LCLS_ | lower control limit for subgroup standard deviation |
_LCLX_ | lower control limit for subgroup mean |
_LIMITN_ | sample size associated with the control limits |
_LSL_ | lower specification limit |
_MEAN_ | process mean ( or ) |
_R_ | value of central line on R chart |
_S_ | value of central line on s chart |
_SIGMAS_ | multiple (k) of standard error of |
_STDDEV_ | process standard deviation ( or ) |
_SUBGRP_ | subgroup-variable specified in the XCHART statement |
_TARGET_ | target value |
_TYPE_ | type (estimate or standard value) of _MEAN_ and _STDDEV_ |
_UCLR_ | upper control limit for subgroup range |
_UCLS_ | upper control limit for subgroup standard deviation |
_UCLX_ | upper control limit for subgroup mean |
_USL_ | upper specification limit |
_VAR_ | process specified in the XCHART statement |
The OUTLIMITS= data set contains one observation for each process specified in the XCHART statement. For an example, see "Saving Control Limits" .
A subgroup standard deviation variable is included if you specify the STDDEVIATIONS option; otherwise, a subgroup range variable is included.
Given a process name that contains eight characters, the procedure first shortens the name to its first four characters and its last three characters, and then it adds the suffix. For example, the procedure shortens the process DIAMETER to DIAMTER before adding the suffix.
Subgroup summary variables are created for each process specified in the XCHART statement. For example, consider the following statements:
proc shewhart data=steel; xchart (width diameter)*lot / outhistory=summary; run;
The data set SUMMARY contains variables named LOT, WIDTHX, WIDTHR, WIDTHN, DIAMTERX, DIAMTERR, and DIAMTERN. The variables WIDTHR and DIAMTERR are included, since the STDDEVIATIONS option is not specified. If you specified the STDDEVIATIONS option, the data set SUMMARY would contain the variables WIDTHS and DIAMTERS rather than WIDTHR and DIAMTERR.
Additionally, the following variables, if specified, are included:
For an example of an OUTHISTORY= data set, see "Saving Summary Statistics" .
Variable | Description |
_ALPHA_ | probability () of exceeding control limits |
_EXLIM_ | control limit exceeded on chart |
_LCLX_ | lower control limit for mean |
_LIMITN_ | nominal sample size associated with the control limits |
_MEAN_ | process mean |
_SIGMAS_ | multiple (k) of the standard error associated with control limits |
subgroup | values of the subgroup variable |
_SUBN_ | subgroup sample size |
_SUBX_ | subgroup mean |
_TESTS_ | tests for special causes signaled on chart |
_UCLX_ | upper control limit for mean |
_VAR_ | process specified in the XCHART statement |
In addition, the following variables, if specified, are included:
Notes:
For an example, see "Saving Control Limits" .
Chapter Contents |
Previous |
Next |
Top |
Copyright © 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.