Peter,
thanks, very nice, this will work for me... could you also help with setting up the code to run the on liner "approx(sort(x), seq(0,1,,length(x)), q)$y" on the rows of a data frame using my example above? So if I cbind z and res,
df<-cbind(z,res)
the "x" in your one liner would be the first 4 column values of each row and "q" is the last (5fth) column value of each row..
thanks again for all the help,
Andras Farkas