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The Western Electric rules are decision rules in statistical process control for detecting out-of-control or non-random conditions on control charts. [1] Locations of the observations relative to the control chart control limits (typically at ±3 standard deviations) and centerline indicate whether the process in question should be investigated for assignable causes.
Date/Time Thumbnail Dimensions User Comment; current: 01:01, 7 October 2009: 230 × 200 (76 KB): GMcGlinn~commonswiki: cleared of svg black block disease : 00:31, 7 October 2009
They are a set of modified Western Electric rules, developed by James Westgard and provided in his books and seminars on quality control. [1] They are plotted on Levey–Jennings charts, wherein the X-axis shows each individual sample, and the Y-axis shows how much each one differs from the mean in terms of standard deviation (SD). The rules ...
The Western Electric rules; The Wheeler rules (equivalent to the Western Electric zone tests [16]) The Nelson rules; There has been particular controversy as to how long a run of observations, all on the same side of the centre line, should count as a signal, with 6, 7, 8 and 9 all being advocated by various writers.
The Nelson rules were first published in the October 1984 issue of the Journal of Quality Technology in an article by Lloyd S Nelson. [2] The rules are applied to a control chart on which the magnitude of some variable is plotted against time. The rules are based on the mean value and the standard deviation of the samples.
The Western Electricity Coordinating Council (WECC) promotes Bulk Electric System (BES) reliability for the entire Western Interconnection system. WECC is the Regional Entity responsible for compliance monitoring and enforcement. In addition, WECC provides an environment for the development of Reliability Standards and the coordination of the ...
It seems like every web page I visit that mentions Western Electric rules, says that rule 4 is violated if just eight consecutive points fall on the same side of the centerline.--216.254.190.174 13:09, 3 July 2009 (UTC) This could be in the interpretation I think. Do you count the first point as part of the deviant set?
Western Electric Walter Andrew Shewhart (pronounced like "shoe-heart"; March 18, 1891 – March 11, 1967) was an American physicist, engineer and statistician. He is sometimes also known as the grandfather of statistical quality control and also related to the Shewhart cycle .