On Nov 26, 2009, at 10:21 PM, ychu066 wrote: > > Hi all, > > I am wondering if R can split the distribution respect to the > median ? I > know it can be done in SAS. ?polygon If you want worked examples there are serveral in the archives: http://search.r-project.org/nmz.html -- David Winsemius, MD Heritage Laboratories West Hartford, CT