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NPCHART Statement |
Variable | Description |
_ALPHA_ | probability () of exceeding limits |
_INDEX_ | optional identifier for the control limits specified with the OUTINDEX= option |
_LCLNP_ | lower control limit for number of nonconforming items |
_LIMITN_ | sample size associated with the control limits |
_NP_ | average number of nonconforming items ( or n_{i}p_{0}) |
_P_ | average proportion of nonconforming items ( or p_{0}) |
_SIGMAS_ | multiple (k) of standard error of X_{i} |
_SUBGRP_ | subgroup-variable specified in the NPCHART statement |
_TYPE_ | type (standard or estimate) of _NP_ |
_UCLNP_ | upper control limit for number of nonconforming items |
_VAR_ | process specified in the NPCHART statement |
Notes:
The OUTLIMITS= data set contains one observation for each process specified in the NPCHART statement. For an example, see "Saving Control Limits" .
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 REJECTED to REJETED before adding the suffix.
Subgroup summary variables
are created for each process
specified in the NPCHART statement.
For example, consider the following statements:
proc shewhart data=input; npchart (rework rejected)*batch / outhistory=summary subgroupn =30; run;
The data set SUMMARY contains variables named BATCH, REWORKP, REWORKN, REJETEDP, and REJETEDN.
Additionally, the following variables, if specified, are included:
For an example of an OUTHISTORY= data set, see "Saving Proportions of Nonconforming Items" .
Variable | Description |
_ALPHA_ | probability () of exceeding control limits |
_EXLIM_ | control limit exceeded on np chart |
_LCLNP_ | lower control limit for number of nonconforming items |
_LIMITN_ | nominal sample size associated with the control limits |
_SIGMAS_ | multiple (k) of the standard error of X_{i} associated with the control limits |
subgroup | values of the subgroup variable |
_SUBNP_ | subgroup number of nonconforming items |
_SUBN_ | subgroup sample size |
_TESTS_ | tests for special causes signaled on np chart |
_UCLNP_ | upper control limit for number of nonconforming items |
_VAR_ | process specified in the NPCHART statement |
In addition, the following variables, if specified, are included:
Notes:
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