From owner-freebsd-chat Sun Aug 17 08:52:40 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id IAA05865 for chat-outgoing; Sun, 17 Aug 1997 08:52:40 -0700 (PDT) Received: from ns1.flask.com (root@ns1.flask.com [207.67.43.2]) by hub.freebsd.org (8.8.5/8.8.5) with ESMTP id IAA05859; Sun, 17 Aug 1997 08:52:38 -0700 (PDT) From: skat@flask.com Received: (from skat@localhost) by ns1.flask.com (8.7.6/8.6.12) id KAA29833; Sun, 17 Aug 1997 10:53:37 -0500 (CDT) Date: Sun, 17 Aug 1997 10:53:36 -0500 (CDT) To: Warner Losh cc: "Brian N. Handy" , Greg Lehey , "Julian H. Stacey" , chat@FreeBSD.ORG, platforms@FreeBSD.ORG Subject: Re: speed test In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-chat@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk On Sun, 17 Aug 1997, Warner Losh wrote: > I've also seen it used, btw, to descibe extremely huge male sex > organs. As to why it doesn't also describe things on the trailing > edge, I know not the answer to that question. > > Warner > Description of three-sigma is context sensitive. Normally, researcher will specify if he means one-tail or two-tail statistics. In the case of Motorola example, they are talking about two-tail, since they want the middle part of bell curve. The two extreams, too small or too large, are rejected parts and there is no reason to differentiate. In your male sex organ example, they are talking about one-tail. for one-tail 1-sigma = 84.1% or 15.9% 2-sigma = 97.7% or 2.3% 3-sigma = 99.8% or 0.2% for the two-tail you double the second number, which becomes the percentatge of extreams, e.g. 1-sigma = 31.8%. The center portion of bell curve ("Norm") becomes 68.2% 1-sigma = 68.2% or 31.8% 2-sigma = 98.9% or 1.1% 3-sigma = 99.9% or 0.1% I believe Motrola was shooting for 6-sigma, which means less than 1.973176w-07% rejection rate. One reject in a lot of 5,000,000 parts. Shin