I wrote: > Perhaps a better generalization of median to higher dimensions is the > Fermat-Weber point, the point that minimizes the sum of the L2 > distances from it to each point. (Average can be similarly > generalized, minimizing the sum of squared L2 distances.) It always > exists (of course) and is unique unless you have an even number of > collinear points and the middle two are different. It is also > rotationally invariant.
A good reference is Christopher G. Small. A Survey of Multidimensional Medians. International Statistical Review, 58(3):263-277. Dec. 1990. -- Rob LeGrand, psephologist [EMAIL PROTECTED] Citizens for Approval Voting http://www.approvalvoting.org/ ____________________________________________________________________________________ Yahoo! Music Unlimited Access over 1 million songs. http://music.yahoo.com/unlimited ---- election-methods mailing list - see http://electorama.com/em for list info
