From: Stan Hilliard, hilli004@tc.umn.edu
Date: 30 Oct 1998
Time: 20:00:00
Remote Name: 160.94.26.37
Hi Dave,
I have researched the relationship between the Mil-Standards 105E&414 and ANSI/ASQC Z1.4&Z1.9. I found the following information in a Journal of Quality Technology article by Ed Schilling -- page131,Vol.13,No2,April 1981. The most important aspects are:
Z1.4 for attributes is the same as Mil-Std-105E.
Z1.9 for variables differs from Mil-Std-414 in the following ways:
(1) The lot size ranges were changed to match those of Z1.4/Mil-Std-105E.
(2) Inspection levels were re-labled to match those of Z1.4/Mil-Std-105E.
(3) The oc-curves of Z1.9 now match Z1.4/Mil-Std-105E for the same lot size and AQL.
The matching of oc-curves allows an inspection operation to switch between attributes and variables without changing its statistical protection.
For more about the strategy of matching oc-curves in general, using two points on the operating characteristic curve, see:
http://www.samplingplans.com/modern3.htm#MATCHING
Thanks for using this discussion forum. Please share this information with other members of the MN section CQE refresher. Stan Hilliard