Control Charts.. Code for 8 Tests for Special Causes

Posted by Paul Magruder on April 19, 2001 7:26 AM

Does anyone know where I might be able to find code that checks for the 8 tests for special causes in a Control Chart? I started writing the code, but am having great difficulty.

Posted by Curtis on June 03, 2001 10:40 PM

Paul,

Try this link:
http://www.qualitydigest.com/apr99/html/body_excel.html

It doesn't give formulas for your 8 tests, but it does give formulas for detecting:
1) 8 points above or below the centerline
2) a run of 8 points above or below the centerline
3) 2 of 3 points are greater than 2 standard deviations from the centerline

HTH