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Shewhart control charts to detect mean and standard deviation shifts based on grouped data
Author(s) -
Steiner Stefan H.,
Lee Geyer P.,
Wesolowsky George O.
Publication year - 1996
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/(sici)1099-1638(199609)12:5<345::aid-qre11>3.0.co;2-m
Subject(s) - control chart , standard deviation , statistics , shewhart individuals control chart , statistical process control , \bar x and r chart , x bar chart , control limits , mathematics , chart , normal distribution , ewma chart , computer science , process (computing) , operating system
A Shewhart control chart is proposed based on gauging theoretically continuous observations into multiple groups. This chart is designed to monitor the process mean and standard deviation for deviations from stability. By assuming an underlying normal distribution, we derive the optimal grouping criterion that maximizes the expected statistical information available in a sample. Control charts based on grouped observations are superior to standard control charts based on variables, such as X and R charts, when the quality characteristic is difficult or expensive to measure precisely, but economical to gauge.