Thank you Mr Snow. I will look into it. Best regards Joyce Lin
On 11 Jan, 2013, at 3:55 AM, Greg Snow <538...@gmail.com> wrote: > To further the understanding of the loess fit and how the tricube weight work > you may want to look at the loess.demo function in the TeachingDemos package. > It will create a scatterplot of the data and show the loess fit, then when > you click on the plot it will show the weights used for predicting at that > point and the fitted line/curve for that point. Click at another place in the > graph and it will show the weights and local fit corresponding to that point. > > > On Tue, Jan 8, 2013 at 9:24 PM, Joyce Lin <joyceli...@gmail.com> wrote: > Thank you Mr Gunter! I will look into it. > > > On Wed, Jan 9, 2013 at 11:59 AM, Bert Gunter <gunter.ber...@gene.com> wrote: > > > As this does not seem to have been answered... > > > > I believe you may misunderstand how loess works. The tricube weights > > are part of the smoothing algorithm and change with each local fit, > > not fixed weights for observations, which is what the "weights" > > argument provides (and initially multiplies the tricube weight, IIRC). > > > > I suggest you consult > > > > ?predict.loess > > > > to get standard deviations of fitted values at existing or new points. > > > > -- Bert > > > > > > > > On Tue, Jan 8, 2013 at 12:57 AM, Joyce Lin <joyceli...@gmail.com> wrote: > > > Hi > > > > > > I am trying to get the tricube weights from the loess outputs as I need > > to > > > calculate an error function which requires the weight. > > > > > > So I have used the following example from the R: > > > > > > cars.lo <- loess(dist ~ speed, cars, span=0.5, degree=1, > > family="symmetric") > > > > > > Then i try to get the weights: > > > > > > cars.lo$weights > > > [1] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 > > 1 1 > > > 1 1 1 1 1 1 1 1 1 1 1 1 1 1 > > > > > > The results are all 1 so i dont think that the tricube weighting are set. > > > May I know what other parameters do i need to tweak to set the weights to > > > tricube weights? Thank you. > > > > > > > > > -- > > > Best regards > > > Joyce Lin > > > > > > [[alternative HTML version deleted]] > > > > > > ______________________________________________ > > > R-help@r-project.org mailing list > > > https://stat.ethz.ch/mailman/listinfo/r-help > > > PLEASE do read the posting guide > > http://www.R-project.org/posting-guide.html > > > and provide commented, minimal, self-contained, reproducible code. > > > > > > > > -- > > > > Bert Gunter > > Genentech Nonclinical Biostatistics > > > > Internal Contact Info: > > Phone: 467-7374 > > Website: > > > > http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm > > > > > > -- > Best regards > Joyce Lin > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > > > > -- > Gregory (Greg) L. Snow Ph.D. > 538...@gmail.com [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
