Hi Pete: RMS deviation (also known as standard deviation) is generally well defined. Could what you have be delta (RMS deviation)[i,j] = SD(i) - SD(j) basically using the delta as a difference operator between two different SD's? This might be one of several possible "signatures" that an analysis would use to compare measurement distributions, or set thresholds for sub-sampling to help delineate clusters. On Sun, 2002-08-18 at 21:54, Peter oledzki wrote: > Hello, > > I'm working on a project at the moment and I've come > across something called delta root mean squared > deviation....does anybody know what this is? > > Could they possily try and explain it to me.....? > > Any help would be much appreciated. > > Cheers > > Pete Oledzki -- Joseph Landman, Ph.D Scalable Informatics LLC email: landman at scalableinformatics.com web: http://scalableinformatics.com phone: +1 734 612 4615