Effect of Testing Normality on Estimating Process Capability Indices
Process capability indices are used to measure whether a manufacturing process meets the specifications. The studies of these indices are usually based on the assumption that the process follows a normal distribution. These include the indices C p , C pk , C pm , and C pmk . When the investigator is...
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Published in | Quality engineering Vol. 18; no. 3; pp. 391 - 395 |
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Main Author | |
Format | Journal Article |
Language | English |
Published |
Milwaukee
Taylor & Francis Group
01.07.2006
Taylor & Francis Ltd |
Subjects | |
Online Access | Get full text |
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Summary: | Process capability indices are used to measure whether a manufacturing process meets the specifications. The studies of these indices are usually based on the assumption that the process follows a normal distribution. These include the indices C
p
, C
pk
, C
pm
, and C
pmk
. When the investigator is uncertain whether the process follows a normal distribution, a test of normality may be used to resolve the uncertainty. If the test accepts the null hypothesis that the process follows a normal distribution, the investigator uses C
p
, C
pk
, C
pm
, or C
pmk
. If the test rejects the null hypothesis, the investigator uses indices under non-normal distributions. Therefore the test of normality is a preliminary test that determines the form of the distribution and the index to use. In this paper we study the effect of the preliminary test of normality on the estimation of the four process capability indices mentioned above. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0898-2112 1532-4222 |
DOI: | 10.1080/08982110600719514 |