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The total median in statistical quality control
Author(s) -
Figueiredo Fernanda,
Gomes M. Ivette
Publication year - 2004
Publication title -
applied stochastic models in business and industry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.413
H-Index - 40
eISSN - 1526-4025
pISSN - 1524-1904
DOI - 10.1002/asmb.545
Subject(s) - statistics , robustness (evolution) , estimator , control chart , sample mean and sample covariance , mathematics , chart , mean value , statistical process control , truncated mean , econometrics , sample size determination , control limits , population , computer science , process (computing) , demography , biochemistry , chemistry , gene , operating system , sociology
In industry, most of the process observations are assumed to come from a normal population, but usually we merely want to control the process mean value. It is thus sensible to find control statistics, which are ‘robust’ to monitor the process mean, giving the expected rate of false alarms whenever that mean is close to the target value, although not under a normal regime. Simulation studies for a few symmetric and asymmetric distributions allow us to suggest the total median as a robust median estimator. We shall here analyse such a robustness, as well as the robustness of the total median chart comparatively to the sample mean chart, whenever we want to control the mean value of a symmetric underlying parent. Some indication is also provided on the comparative out‐of‐control behaviour of the two charts. Copyright © 2004 John Wiley & Sons, Ltd.