Dear Marc, > -----Original Message----- > From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Marc > Girondot via R-help > Sent: Monday, January 30, 2017 12:19 PM > To: R-help Mailing List <r-help@r-project.org> > Subject: [R] g parameter for deltaMethod() as a function > > Hi everyone, > > I try to use the Default S3 method DeltaMethod() from car package, but I > have some problems when I try to use a function as the "g" parameter. I > don't know if it is possible anyway. I hope that you could tell me:
I don't see how that would work. From ?deltaMethod: "g [the second argument]: A quoted string that is the function of the parameter estimates to be evaluated; see the details below." A possible solution would be to write a wrapper function that prepares a proper call to deltaMethod(). I hope this helps, John -------------------------------------- John Fox, Professor McMaster University Hamilton, Ontario, Canada Web: socserv.mcmaster.ca/jfox > > Here an example from the help of deltaMethod(). It works and I > understand well (I think at least !). > > library(car) > m1 <- lm(time ~ t1 + t2, data = Transact) deltaMethod(coef(m1), "t1/t2", > vcov.=vcov(m1)) > > ############### > > I would like do the same with a function instead of "t1/t2": > > try_g <- function(...) { > par <- list(...) > return(par$t1/par$t2) > } > > try_g(t1=1, t2=2) > deltaMethod(coef(m1), "try_g", vcov.=vcov(m1)) > > But I get an error: > > Error in as.data.frame.default(x[[i]], optional = TRUE) : > cannot coerce class ""function"" to a data.frame > > If someone could give me the solution... or tell me if it is impossible > ! > > Thanks > > Marc > > PS. In fine I would like using deltaMethod() to produce a confidence > interval after fitting a model using ML with optim. > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.