Bootstrap Confidence Interval for Robust Cpk Index
A Cpk index is the most widely used measure of process capability. A better understanding and interpretation of Cpk is by constructing its confidence interval. The construction of such intervals, are normally based on the assumption that the measurements process can be treated as samples from...
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| Main Authors: | , |
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| Format: | Article |
| Language: | English English |
| Published: |
Institute for Mathematical Research
2008
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| Online Access: | http://psasir.upm.edu.my/id/eprint/12454/1/artikel_5_vol1_no2.pdf http://psasir.upm.edu.my/id/eprint/12454/ |
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| Summary: | A Cpk index is the most widely used measure of
process capability. A better understanding and
interpretation of Cpk is by constructing its
confidence interval. The construction of such
intervals, are normally based on the assumption
that the measurements process can be treated as
samples from a normal distribution.
Nevertheless, many processes are not normal and
have a heavy tail distribution, which probably
due to the presence of outliers in the data. An
alternative approach is to use a bootstrap
confidence interval estimate of Cpk index which
is based on robust method. The advantage of
this estimate is that its usage does not depend on
any distribution. A numerical example is
presented to evaluate the performance of the
bootstrap confidence interval of the robust Cpk
index. The result indicates that the bootstrap
confidence interval estimate based on the robust
Cpk is better than the classical Cpk index. |
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