[R] add points to xyplot() from alternate data frame

[Dylan Beaudette]

Hi,

I am using xyplot() to produce a mutli-panel plot of logistic regression 
response curves. I would like to include symbols denoting the original binary 
response observations, however this data is located in a different dataframe 
than what xyplot() is using.

I am first plotting the smooth, predicted response curves, and would like to 
add points to the figure. In base graphics this would be a simple matter of 
plot(x,y, data=predicted) ; points(x,y, data=original). 

is there a similar way to accomplish this in lattice, i.e. plotting from 
different sources to the same figure ?

thanks


-- 
Dylan Beaudette
Soil Resource Laboratory
http://casoilresource.lawr.ucdavis.edu/
University of California at Davis
530.754.7341