Dear Clara, The warning is nothing to worry about. If start values aren't specified, box.cox.powers() uses optimize() to find start values for each transformation parameter (in this case, there's only one) prior to using optim() to maximize the (possibly multivariate) likelihood. In the course of finding start values, optimize() apparently tried an unreasonable value. In this case, box.cox.powers(income, start=1) gives you the same result minus the warning.
Regards, John -------------------------------- John Fox, Professor Department of Sociology McMaster University Hamilton, Ontario, Canada L8S 4M4 905-525-9140x23604 http://socserv.mcmaster.ca/jfox > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > project.org] On Behalf Of [EMAIL PROTECTED] > Sent: February-06-08 1:05 PM > To: R-help@r-project.org > Subject: [R] box.Cox.powers() warning > > Dear Rlist, > > Using an example in box.cox.powers() help, I have the following warning > message. > > example: > library(car) > >attach(Prestige) > > > box.cox.powers(income) > Box-Cox Transformation to Normality > > Est.Power Std.Err. Wald(Power=0) Wald(Power=1) > 0.1793 0.1108 1.6179 -7.4062 > > L.R. test, power = 0: 2.7103 df = 1 p = 0.0997 > L.R. test, power = 1: 47.261 df = 1 p = 0 > Warning message: > In optimize(f = function(lambda) univ.neg.kernel.logL(x = X[, j], : > NA/Inf replaced by maximum positive value > > I do not know the reason for such warning message. > Can someone help me on this matter? > > Best regards, > Clara Cordeiro > > > sessionInfo() > R version 2.6.1 (2007-11-26) > i386-pc-mingw32 > > locale: > LC_COLLATE=Portuguese_Portugal.1252;LC_CTYPE=Portuguese_Portugal.1252;L > C_MONETARY=Portuguese_Portugal.1252;LC_NUMERIC=C;LC_TIME=Portuguese_Por > tugal.1252 > > attached base packages: > [1] stats graphics grDevices utils datasets methods base > > other attached packages: > [1] nnet_7.2-38 car_1.2-7 MASS_7.2-38 FitAR_1.0 > leaps_2.7 > [6] lattice_0.17-2 > > loaded via a namespace (and not attached): > [1] grid_2.6.1 tools_2.6.1 > > ______________________________________________ > 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. ______________________________________________ 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.
