I have been made aware that the genelogic dilution study can't be re-distributed http://qolotus02.genelogic.com/DataSets.nsf/Agreement?OpenPage so ive removed the data from http://www.biostat.jhsph.edu/~ririzarr/affycomp/index.html and added a link to the genelogice page were you can obtain it from. apologies for any inconvenience, rafael