The capability index when some assumptions are not satisfiedanalysis and empirical comparisons
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Universidad de Granada
info
ISSN: 1133-3197, 1697-5731
Year of publication: 2016
Issue Title: Datos, información y conocimiento en Economía
Volume: 34
Issue: 3
Pages: 649-674
Type: Article
More publications in: Estudios de economía aplicada
Abstract
The process capability index (PCI) evaluates the ability of a process to produce items with certain quality requirements. The PCI depends on the process standard deviation, which is usually unknown and estimated by using the sample standard deviation. The construction of confidence intervals for the PCI is also an important topic. The usual estimator of the PCI and its corresponding confidence interval are based on various assumptions, such as normality, the fact that the process is under control, or samples selected from infinite populations. The main aim of this paper is to investigate the empirical properties of estimators of the PCI, and analyze numerically the effect on confidence intervals when such assumptions are not satisfied, since these situations may arise in practice.
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