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The Variable Sample Size X ¯ Chart with Estimated Parameters
Author(s) -
Castagliola Philippe,
Zhang Ying,
Costa Antonio,
Maravelakis Petros
Publication year - 2012
Publication title -
quality and reliability engineering international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 62
eISSN - 1099-1638
pISSN - 0748-8017
DOI - 10.1002/qre.1261
Subject(s) - control chart , chart , statistics , \bar x and r chart , sample size determination , statistical process control , x bar chart , process (computing) , control limits , mathematics , computer science , operating system
The VSS X ¯ chart, dedicated to the detection of small to moderate mean shifts in the process, has been investigated by several researchers under the assumption of known process parameters. In practice, the process parameters are rarely known and are usually estimated from an in‐control Phase I data set. In this paper, we evaluate the (run length) performances of the VSS chart when the process parameters are estimated, we compare them in the case where the process parameters are assumed known and we propose specific optimal control chart parameters taking the number of Phase I samples into account.