Talk to a local statistician or study a book on regression. You do not understand how regression works.
In R, see ?contrasts . -- Bert Bert Gunter Genentech Nonclinical Biostatistics (650) 467-7374 "Data is not information. Information is not knowledge. And knowledge is certainly not wisdom." Clifford Stoll On Fri, Sep 19, 2014 at 5:55 AM, Angel Rodriguez <angel.rodrig...@matiainstituto.net> wrote: > Well, a variable with values 0/1 is useful for calculating observed > probabilities by groups. But it is not diffcult to have the same variable > both as numeric and as a factor in the dataframe and use each variation > depending on the analysis. > > Angel > > ________________________________ > > De: Duncan Murdoch [mailto:murdoch.dun...@gmail.com] > Enviado el: vie 19/09/2014 14:22 > Para: Angel Rodriguez; r-help@r-project.org > Asunto: Re: [R] See the numeric codes of a factor > > > > On 19/09/2014 8:12 AM, Angel Rodriguez wrote: >> Re: [R] See the numeric codes of a factor >> Thank you, Duncan. So isn't it possible to add labels to a variable >> with numeric values 0/1? This kind of variable is very useful for >> logistic regression, for example, but I'd rather have its >> categories labelled. > > I think you are thinking of how you have done things in some other > system. In R, a factor is fine in logistic regression, regardless of > the fact that internally values are stored as 1 and 2. > > Duncan Murdoch > >> Angel >> >> ------------------------------------------------------------------------ >> *De:* Duncan Murdoch [mailto:murdoch.dun...@gmail.com] >> *Enviado el:* vie 19/09/2014 13:32 >> *Para:* Angel Rodriguez; r-help@r-project.org >> *Asunto:* Re: [R] See the numeric codes of a factor >> >> On 19/09/2014, 6:53 AM, Angel Rodriguez wrote: >> > Dear Subscribers, >> > >> > I want to label a numeric variable 0="Bad" /1="Good". I understand >> the only way is to transform it into a factor variable. >> > >> > Is there a way to check that the numeric values of the new factor >> variable are 0 and 1 and not 1 and 2? >> >> If you apply as.numeric() to a factor, you won't get a zero value. >> Internal factor values start at 1. >> >> So I wouldn't rely on the internal storage to achieve whatever it is you >> want to achieve. Use explicit computation, e.g. >> >> words <- ifelse(var == 0, "Bad", ifelse(var == 1, "Good", NA)) >> values <- ifelse(words == "Bad", 0, ifelse(words == "Good", 1, NA)) >> >> Duncan Murdoch >> >> >> > > > > > [[alternative HTML version deleted]] > > ______________________________________________ > 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.
