Date: Fri, 29 Dec 2000 15:04:43 -0200 (EDT)
From: Marcelo Menezes Reis <[EMAIL PROTECTED]>
Subject: Sudden shift of level
Greetings
Does anybody know an algorithm, or a "statistical rule", to identify
sudden shifts of level in Control Charts (used in Statistical Process
control)? The idea is to implement such algorithm in a "pattern
recognizer" which will identify outliers, stratification, mixtures, etc.
Happy Millenium to all.
Marcelo Menezes Reis
Computer Science and Statistics Department
Universidade Federal de Santa Catarina
Florianópolis,SC,BRAZIL
Marcelo,
The so-called Western Electric Rules may be what you are looking for.
The ones that go, ANY OF 1 point 3 sigma out, OR, 2 out of 3 on one
side, 2 sigma out, OR 8 in a row, 1 sigma out on one side. These
effectively incorporate 'history' between points, which is what the
CUMSUM does, with a lot more intellectual work.
I have a supervisor and user level instruction set for doing this, which
can be maintained on paper, at the work station. (what a concept! he
said), if you like.
Jay
--
Jay Warner
Principal Scientist
Warner Consulting, Inc.
4444 North Green Bay Road
Racine, WI 53404-1216
USA
Ph: (262) 634-9100
FAX: (262) 681-1133
email: [EMAIL PROTECTED]
web: http://www.a2q.com
The A2Q Method (tm). What do you want to improve today?
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