Detection of Non-Random Patterns in Shewhart Control Charts: Methods and Applications
نویسنده
چکیده
The main purpose of this article is the development and the study of runs rules applied to a Shewhart type control chart for the mean in order to detect non-random patterns in Phase I, when we are interested to conclude if the process is in a stable condition for the first twenty five or thirty samples in order to estimate the process’ parameters. A characterization scheme such as which rule is better for which pattern, is given. This characterization is extremely useful to the practitioners. A few applications of the proposed methodology are presented.
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Shewhart charts are the main tools for statistical process control. They are used for detecting assignable causes which affect quality of process output. From them, X and MR charts are two univariate control charts for monitoring mean and variation of measurable quality characteristics. The main drawbacks of these charts are: weakness of X chart against non-normal distribution of process data,...
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