There is function for linear combination in car package as well. Best Ronggui
On Sun, Dec 14, 2008 at 1:42 PM, Andrew Robinson <a.robin...@ms.unimelb.edu.au> wrote: > > estimable in the gmodels package provides point estimates, standard > errors and confidence intervals for arbitrary linear combinations of > model parameters. I don't know for non-linear combinations, though. > > Cheers > > Andrew > > On Sat, Dec 13, 2008 at 11:33:12PM -0600, Stas Kolenikov wrote: >> Those commands provide point estimates, standard errors and confidence >> intervals based on linear combination of parameters or >> linearization/delta-method, respectively. R's contrasts appear to be >> limited to a single factor and combinations that sum up to zero. >> >> I am too so used to this Stata's concept, I now think it's odd R does >> not seem to have it readily identifiable in two-three search commands. >> And I would not believe R does not have this functionality, it must be >> hiding somewhere! :)) >> >> On 12/13/08, David Winsemius <dwinsem...@comcast.net> wrote: >> > >> > On Dec 12, 2008, at 11:14 AM, Marc Mar? Dell'Olmo wrote: >> > >> > >> > > Hello all, >> > > >> > > Does anyone know if there exists any function in R that resembles the >> > > "lincom" and "nlcom" of STATA?. These functions computes point >> > > estimates, standard errors, significance levels, confidence intervals, >> > > etc. for linear and non linear combinations of previous estimated >> > > parameters. Down here you've got links to descriptions of the >> > > functions of STATA >> > > >> > > nlcom: >> > > http://www.stata.com/help.cgi?nlcom >> > > lincom: >> > > http://www.stata.com/help.cgi?lincom >> > > >> > >> > I did not find a description of the mathematical operations that let me >> > understand exactly what lincom is doing, but suspect that you should be >> > looking at how R handles contrasts. The help pages reference ch 2 of >> > "Statistical Models in S". The search at the console prompt would be: >> > >> > ?C >> > ?contrasts >> > ?se.contrast >> > ?model.tables >> > >> >> -- >> Stas Kolenikov, also found at http://stas.kolenikov.name >> Small print: I use this email account for mailing lists only. >> >> ______________________________________________ >> 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. > > -- > Andrew Robinson > Department of Mathematics and Statistics Tel: +61-3-8344-6410 > University of Melbourne, VIC 3010 Australia Fax: +61-3-8344-4599 > http://www.ms.unimelb.edu.au/~andrewpr > http://blogs.mbs.edu/fishing-in-the-bay/ > > ______________________________________________ > 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. > -- HUANG Ronggui, Wincent Tel: (00852) 3442 3832 PhD Candidate, City University of Hong Kong Website: http://ronggui.huang.googlepages.com/ RQDA project: http://rqda.r-forge.r-project.org/ ______________________________________________ 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.
