tag:blogger.com,1999:blog-6977755959349847093.post465922820856379621..comments2024-03-01T21:53:15.921-08:00Comments on The Pith of Performance: Subjugation to the SigmasNeil Guntherhttp://www.blogger.com/profile/11441377418482735926noreply@blogger.comBlogger11125tag:blogger.com,1999:blog-6977755959349847093.post-76809423402281465492012-07-03T15:44:22.875-07:002012-07-03T15:44:22.875-07:00Hi Carl,
Thank you and welcome!
BTW, this sigmas...Hi Carl,<br /><br />Thank you and welcome!<br /><br />BTW, this sigmas business is going to become a hot topic on the web as of tomorrow when CERN makes their public statement about the status of the latest Higgs data from the LHC.<br /><br />For example, and quoting: <br />"... 5 sigma, meaning that it has just a 0.00006% chance of being wrong. The ATLAS and CMS experiments are each seeing signals between 4.5 and 5 sigma, just a whisker away from a solid discovery claim." <br /><br />5 sigma is the minimum bar for particle physics data. It's also just as well to keep in mind that the confidence level doesn't tell the whole story. <br /><br />Last year, a different CERN-related experiment was seeing superluminal neutrinos (i.e., Einstein busters) at the 6-sigma level. After eventually finding the loose connector in their detector, those revolutionary neutrinos suddenly disappeared http://is.gd/WWaj7F<br /><br />Forearmed by that fiasco, The Higgs boys are very unlikely to have that problem, but they are still going to have to demonstrate that their 4+ sigma bumps are really The Higgs.Neil Guntherhttps://www.blogger.com/profile/11441377418482735926noreply@blogger.comtag:blogger.com,1999:blog-6977755959349847093.post-45765674520519928312012-07-03T14:20:37.660-07:002012-07-03T14:20:37.660-07:00Hey,
Very nice site. I came across this on Google,...Hey,<br />Very nice site. I came across this on Google, and I am stoked that I did. <br />I will definitely be coming back here more often.<br />Wish I could add to the conversation and bring a bit more to the table, but am just taking in as much info as I can at the moment.<a href="http://www.1stcourses.com" rel="nofollow">Six Sigma Certification</a>Anonymoushttps://www.blogger.com/profile/18133765657965222588noreply@blogger.comtag:blogger.com,1999:blog-6977755959349847093.post-63209974247515527262011-08-31T09:35:19.762-07:002011-08-31T09:35:19.762-07:00Salesforce.com is holding a big conference in down...Salesforce.com is holding a big conference in downtown San Francisco at the moment (30,000 attendees) and I happened across this comment in their <a href="http://en.wikipedia.org/wiki/Salesforce.com#Criticisms" rel="nofollow">Wikipedia entry</a>:<br /><br /><em>"The service has suffered some downtime; during an outage in January 2009 services were unavailable for at least 40 minutes, affecting thousands of businesses."</em><br /><br />But that's about four 9s availability!<br /><br />Of course, they couldn't afford another outage in 2009 in order to maintain that availability level. And that level is the statistical <b>mean</b>, which says nothing about <b>variance</b>. :)Neil Guntherhttps://www.blogger.com/profile/11441377418482735926noreply@blogger.comtag:blogger.com,1999:blog-6977755959349847093.post-87898617919681238042011-08-24T13:31:45.535-07:002011-08-24T13:31:45.535-07:00This just in from Twitter...
@OReillyMedia O'...This just in from Twitter...<br /><br />@OReillyMedia O'Reilly Media<br />100% uptime. It's not just about technology. CIO <a href="http://twitter.com/Reichental" rel="nofollow">@Reichental</a> discusses the value of good change management: <a href="http://radar.oreilly.com/2011/08/it-leadership-how-why-process-action.html" rel="nofollow">oreil.ly/mTlYDw</a>Neil Guntherhttps://www.blogger.com/profile/11441377418482735926noreply@blogger.comtag:blogger.com,1999:blog-6977755959349847093.post-50725382663294382302011-08-24T09:18:47.149-07:002011-08-24T09:18:47.149-07:00I'll see that and raise you 5 ...sigma? :)
Th...I'll see that and raise you 5 ...sigma? :)<br /><br />There's something of a technical contradiction in attempting to apply "6sigma" improvement (e.g., SPC) to computer performance data. The assumption is that the samples are discrete point events (defects), whereas almost all computer performance data are time series where the events have already been averaged over some predefined sampling time interval.Neil Guntherhttps://www.blogger.com/profile/11441377418482735926noreply@blogger.comtag:blogger.com,1999:blog-6977755959349847093.post-49683617355101795972011-08-24T05:15:30.373-07:002011-08-24T05:15:30.373-07:00Here's another interesting tidbit: how's ...Here's another interesting tidbit: how's the expected deviation of a series conditional upon being >= 6 sigmas different than any other sigma.jeffhttps://www.blogger.com/profile/08443483295816194142noreply@blogger.comtag:blogger.com,1999:blog-6977755959349847093.post-42806549533544609262011-08-23T15:41:11.137-07:002011-08-23T15:41:11.137-07:00No worries.
I could delete one, but I would have...No worries. <br /><br />I could delete one, but I would have to get really worked up about it. :)Neil Guntherhttps://www.blogger.com/profile/11441377418482735926noreply@blogger.comtag:blogger.com,1999:blog-6977755959349847093.post-72806726769739874312011-08-23T15:33:37.526-07:002011-08-23T15:33:37.526-07:00My apologies about posting the question twice. The...My apologies about posting the question twice. The first time, the message I got seemed to suggest it hadn't posted.Efriquehttps://www.blogger.com/profile/08526031804261484547noreply@blogger.comtag:blogger.com,1999:blog-6977755959349847093.post-3067245044179788062011-08-23T07:38:53.714-07:002011-08-23T07:38:53.714-07:00That, of course, is part of the point of this post...That, of course, is part of the point of this post: big talk, little measurement.<br /><br />Major web sites often do have enough data to support claims about 3 to 5 nines availability.<br /><br />As an aside, particle physics measurements require 5sigma levels to be considered valid. Current measurements at the LHC, regarding the existence of the Higgs boson, are more like 2sigma.Neil Guntherhttps://www.blogger.com/profile/11441377418482735926noreply@blogger.comtag:blogger.com,1999:blog-6977755959349847093.post-35896699155994154772011-08-23T02:57:46.873-07:002011-08-23T02:57:46.873-07:00How often is it the case that actual data distribu...How often is it the case that actual data distributions - even of sample averages - are sufficiently close to normal out to 6 sigma that those percentages are at all meaningful?Efriquehttps://www.blogger.com/profile/08526031804261484547noreply@blogger.comtag:blogger.com,1999:blog-6977755959349847093.post-19666813716249605702011-08-23T02:54:55.861-07:002011-08-23T02:54:55.861-07:00How often are distributions - even of sample means...How often are distributions - even of sample means - normal out to 6-sigmas?Efriquehttps://www.blogger.com/profile/08526031804261484547noreply@blogger.com