That is not an appropriate way to fit a degree-10 polynomial (in any language, if fitting a degree-10 polynomial is in fact an appropriate statistical analysis, which seems unlikely).
On Sun, 30 Jul 2006, Carnell, Rob C wrote: > NIST maintains a repository of Statistical Reference Datasets at > http://www.itl.nist.gov/div898/strd/. I have been working through the > datasets to compare R's results to their references with the hope that > if all works well, this could become a validation package. What does it validate? The R user's understanding of numerical methods? > All the linear regression datasets give results with some degree of > accuracy except one. The NIST model includes 11 parameters, but R will > not compute the estimates for all 11 parameters because it finds the > data matrix to be singular. > > The code I used is below. Any help in getting R to estimate all 11 > regression parameters would be greatly appreciated. > > I am posting this to the R-devel list since I think that the discussion > might involve the limitations of platform precision. > > I am using R 2.3.1 for Windows XP. > > rm(list=ls()) > require(gsubfn) That is not needed. > defaultPath <- "my path" > > data.base <- "http://www.itl.nist.gov/div898/strd/lls/data/LINKS/DATA" > > reg.data <- paste(data.base, "/Filip.dat", sep="") > > model <- > "V1~V2+I(V2^2)+I(V2^3)+I(V2^4)+I(V2^5)+I(V2^6)+I(V2^7)+I(V2^8)+I(V2^9)+I > (V2^10)" > > filePath <- paste(defaultPath, "//NISTtest.dat", sep="") > download.file(reg.data, filePath, quiet=TRUE) filePath <- url("http://www.itl.nist.gov/div898/strd/lls/data/LINKS/DATA/Filip.dat") will suffice. > A <- read.table(filePath, skip=60, strip.white=TRUE) > lm.data <- lm(formula(model), A) > > lm.data lm(V1 ~ poly(V2, 10), A) works. > kappa(model.matrix(V1 ~ poly(V2, 10, raw=TRUE), A), exact=TRUE) [1] 1.767963e+15 shows the design matrix is indeed numerically singular by the naive method. -- Brian D. Ripley, [EMAIL PROTECTED] 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 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel