On 03/15/2011 04:18 AM, Sébastien Durand wrote: > Hello Dr. Pebesma and all other 1989 readers... > > Believe me, I would have been much happier, if I could comprehend this tiny > little detail that you refer to as : > >> It looks quite OK; I suspect however that instead of using >> mean(s.v$gamma) for SSTot, for this mean the same weighting scheme >> should have been used. > > I still do not understand what you mean by that. I am very sorry for that > and yes I now feel stupid, sincerely I am doing my best to graps very old > notions. > > In my function, it is the weighted residual that are squared, that part is > ok, but now you are telling me that I am not using to proper "mean" > reference, that in fact the "same weighting scheme should be used on that ... > ??? Did you meant "mean(vario$gamma)*weig" ??? > > I would like to receive an explanation for this?
You're comparing a weighted fit to an unweighted mean. If you want to evaluate the fit (by R2), the corresponding null-model should use the same weights, IMO. Given weights w and values sv$gamma, that would be sum(w * sv$gamma)/sum(w) rather than mean(sv$gamma). Or, alternatively, weighted.mean(sv$gamma, w) > Sincerely! > > > The other software is GS+ > > S. > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-geo -- Edzer Pebesma Institute for Geoinformatics (ifgi), University of Münster Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251 8333081, Fax: +49 251 8339763 http://ifgi.uni-muenster.de http://www.52north.org/geostatistics e.pebe...@wwu.de _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
