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Control charts to monitor rates and proportions
Author(s) -
Lee Ho Linda,
Fernandes Fidel Henrique,
Bourguig Marcelo
Publication year - 2019
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/qre.2381
Subject(s) - control chart , bernoulli's principle , statistics , simplex , control limits , gamma distribution , mathematics , distribution (mathematics) , versa , computer science , engineering , combinatorics , mathematical analysis , process (computing) , database , aerospace engineering , operating system
In this paper, we call attention for monitoring proportions and rates when they are not results of Bernoulli experiments. To deal with this problem, usually control charts based on Beta distributions are built as this distribution is a well‐known one. However, in practice, there are other distributions to be considered as Simplex and Unit Gamma distributions. The impact of the speed to signal a shift in the average proportion in terms of out‐of‐control average run length is measured when the control limits determined under a Beta distribution is equivocally used to monitor individual rates from Simplex or Unit Gamma distributions or vice versa.