You probably have missing values in your y data. Try: ... panel.abline(h=mean(y,na.rm=TRUE)) ...
-- Bert Gunter Genentech Non-Clinical Statistics South San Francisco, CA "The business of the statistician is to catalyze the scientific learning process." - George E. P. Box > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Martin > Henry H. Stevens > Sent: Tuesday, December 20, 2005 10:30 AM > To: r-help@stat.math.ethz.ch > Subject: [R] panel function > > R v. 2.2.0 on Mac OS 10.4.3 > lattice v. 0.12-11 > > I am trying to add a horizontal panel mean line to a series > of panels > in a trellis plot (i.e. a horizontal line at the mean of y for each > individual panel). I have tried innumerable ways to do this, > including the code below, but if it works at all, it merely puts a > horizontal line in the last panel. > > xyplot(diss ~ Nut-7|Size, data=dathdiss, pch=1, jitter.data=TRUE, > panel=function(x,y,...){ > panel.xyplot(x,y) > panel.abline(a=mean(y),b=0) #This results in the > correct line in the > last panel, but no other lines at all. > }) > > Any and all thoughts are appreciated. > Thank you kindly, > Hank > > Dr. Martin Henry H. Stevens, Assistant Professor > 338 Pearson Hall > Botany Department > Miami University > Oxford, OH 45056 > > Office: (513) 529-4206 > Lab: (513) 529-4262 > FAX: (513) 529-4243 > http://www.cas.muohio.edu/~stevenmh/ > http://www.muohio.edu/ecology/ > http://www.muohio.edu/botany/ > "E Pluribus Unum" > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html