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Some Process Capability Indices are More Reliable than One Might Think
Author(s) -
Kotz Samuel,
Pearn Wen Lea,
Johnson N. L.
Publication year - 1993
Publication title -
journal of the royal statistical society: series c (applied statistics)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.205
H-Index - 72
eISSN - 1467-9876
pISSN - 0035-9254
DOI - 10.2307/2347409
Subject(s) - process (computing) , computer science , econometrics , management science , statistics , mathematics , engineering , programming language
SUMMARY In this paper we obtain formulae for exact expected values and standard deviations of estimators of certain process capability indices discussed by Bissell. In particular, we show that for the index C p k Bissell's formula gives values for the standard deviation which are too high especially when the actual population mean value is close to (or equal to) the average of the upper and lower specification limits.