I'm struggling to find a way to add a line (abline, lline or lmline) to a single panel of a lattice plot. In one panel, there is an outlier and I'd like to include a second lmline fit to the data without this point. I've looked through nine pages of the archives on lattice and it wasn't obvious (to me) what additional search keyword to add to hone in on this, although I would think that it's an issue that would have come up before. I've played around with the groups, subscripts and panel.superpose arguments and looked through the lattice.par.get list but haven't found the way to do it yet. Here is the structure of thecommand that I'm working with, but with the abline appearing on all (3 in my case) panels: xyplot(y ~ x | z, data = my.df, panel=function(x,y) { panel.xyplot(x,y) panel.lmline(x,y) panel.abline(c(0.25,0.79,lty=2) #would like this only on panel 1 }, layout=c(3,1),aspect="x", scales=list(cex=1.2), xlab=list(label="x"), ylab=list(label="y") Thanks for any help or directions thereto, in advance. Ken ____________________ Ken Knoblauch Inserm U 371 Cerveau et Vision 18 avenue du Doyen Lepine 69675 Bron cedex France tel: +33 (0)4 72 91 34 77 fax: +33 (0)4 72 91 34 61 portable: 06 84 10 64 10