Good morning, I am Marta Colombo,student at Politecnico,Milan. I am studying local regression models and I am using loess function. My problem is that when I have a loess object I don't know how to display the fitted surface; in fact, while in S when you have a loess object you can see it writing plot(object), in R this dosen't work. Also I'd like to know if there is something like the S function pointwise that computes upper and lower confidence intervals. Thank you very much for your attention. Marta Colombo
display of a loess fitted surface
2 messages · Marta Colombo, Brian Ripley
On Thu, 18 Aug 2005, Marta Colombo wrote:
I am Marta Colombo,student at Politecnico,Milan. I am studying local regression models and I am using loess function. My problem is that when I have a loess object I don't know how to display the fitted surface; in fact, while in S when you have a loess object you can see it writing plot(object), in R this dosen't work.
Why not use S if that does what you want? There are examples using R in MASS, for example: see the ch04.R and ch15.R scripts.
Also I'd like to know if there is something like the S function pointwise that computes upper and lower confidence intervals.
(Do you mean upper and lower confidence limits?) Thats a more general question. Many of R's predict() methods can construct confidence (and tolerance) intervals. If not, it is easy to do this yourself, as pred_obj$fit-/+pred_obj$se*qnorm(alpha/2).
Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595