Bivariate control charts with double sampling
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Data
2008-01-01
Autores
Costa, A. F. B.
Machado, M. A. G. [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Routledge Journals, Taylor & Francis Ltd
Resumo
In this article, we consider the T(2) chart with double sampling to control bivariate processes (BDS chart). During the first stage of the sampling, n(1) items of the sample are inspected and two quality characteristics (x; y) are measured. If the Hotelling statistic T(1)(2) for the mean vector of (x; y) is less than w, the sampling is interrupted. If the Hotelling statistic T(1)(2) is greater than CL(1), where CL(1) > w, the control chart signals an out-of-control condition. If w < T(1)(2) <= CL(1), the sampling goes on to the second stage, where the remaining n(2) items of the sample are inspected and T(2)(2) for the mean vector of the whole sample is computed. During the second stage of the sampling, the control chart signals an out-of-control condition when the statistic T(2)(2) is larger than CL(2). A comparative study shows that the BDS chart detects process disturbances faster than the standard bivariate T(2) chart and the adaptive bivariate T(2) charts with variable sample size and/or variable sampling interval.
Descrição
Palavras-chave
the Hotelling statistic T(2), bivariate processes, double sampling
Como citar
Journal of Applied Statistics. Abingdon: Routledge Journals, Taylor & Francis Ltd, v. 35, n. 7, p. 809-822, 2008.