Talk:Nelson rules

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I couldn't find the reference stated in the following sentence on the publisher's web site: "They were first published in the October 1984 issue of the Journal of Quality Technology in an article by Lloyd S Nelson."

Specifically, I looked on http://www.asq.org/pub/jqt/past/backissues/1984/october.html and didn't find any related articles. Can someone find the correct citation?

[edit] Small Confusion around Rule 3

Very informative and useful page, but I would like to clear up a couple of things which I find unclear with respect to Rule 3:

Would the following set of data be considered to include 5 points in a row continually increasing or 6 points in a row increasing?

10 1 2 3 4 5 6 0

Also, I guess that if a value is repeated, then it is NOT considered as increasing, could someone confirm this?

Similar questions exist for Rule 4, but I would hope that the same answers apply to both.

SparkyMarky 06:58, 19 December 2006 (UTC)

My understanding (in an uninformed way) is that "10 1 2 3 4 5 6 0" is six points in a continually increasing sequence. It is also five points and 4 points and 3 points in a sequence etc. It is six points (with 5 increasings). I have never seen a definition of what to do when values are equal. However in a real system, there will be noise on the measurements and an equality could probably be treated as either increasing or not at your choice. -- SGBailey 08:27, 22 December 2006 (UTC)