I read in !emc-pstc that Doug McKean <dmck...@corp.auspex.com> wrote (in <007501c16cba$d2481220$3e3e3...@corp.auspex.com>) about '80/80 rule for euro compliance?', on Tue, 13 Nov 2001: >I have never liked the 80-80 Rule as liberal as some may >think it is. I've even toyed with the idea of writing a paper >about it, but I think I'd go to sleep writing it, let alone >presenting it. > >If you take the basic premise statistically and work out the >numbers yourself, you will surprised at the results. > >Say you have a given a total population of 100 products. >In that total population, you expect 20 products to fail. >Now, you take 5 samples from that population and >calculate the probability of failure. > >The chances of 1 product failing in the 5 samples drawn >is 42%. The probability of 2 products failing from 5 samples >in the above example is 21%. > >IOW, you have a 1 in 5 chance of failing the 80-80 Rule >by following it. That's bad. And if your company is into >the practice of shipping relatively small amounts of product, >that can be bad also.
This is what happens if you apply the 80/80 rule to small numbers of product. It's really applicable only to high-volume production (mostly consumer) products, where some statistical criterion has to be set to eliminate the need for 100% testing. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Eat mink and be dreary! ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
