My summary can be found at http://wserv1.dl.ac.uk/list-archive-public/ccp4bb/2003-10/msg00431.html Anthony Anthony Duff Telephone: 02 9717 3493 Mob: 043 189 1076 -----Original Message----- From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of Richard Gillilan Sent: Friday, 12 December 2008 9:37 AM To: [log in to unmask] Subject: Re: [ccp4bb] definition of I Sigma I There was a detailed and useful discussion of this on this list back around Dec 1, 2003. If you search in the archives for "I on sig I" you will find it. Best Richard On Dec 10, 2008, at 5:14 PM, ANDY DODDS wrote: > Hi, > > does anyone have a definition of I Sigma I please. Any definitions > that i have found are not very informative for novices. > > > thanks > > andy