[R] Dummies in R
Liaw, Andy
andy_liaw at merck.com
Thu Apr 29 15:25:35 CEST 2004
> From: Susana Bird
>
> Dear all,
>
> my problem is following. I know Stata, but currently I have
> to use R.
I have the opposite of your problem: I don't know Stata, but I don't have
to use Stata. 8-)
> Could You please help in finding the analogy to R.
>
> (1) creating of City-Dummy.
>
> I know in Stata:
>
> g byte city=0
> replace city=1 if city==12&year==2000
>
> and
>
> (2) Create a Time-Dummy-Variable
>
> g byte T2000=0
> replace T2000=1 if year==2000
Because I don't know Stata, I'm not sure what those commands do, but I'll
take a crack at guessing anyway. If `year' is a vector of numbers, you can
do something like:
T2000 = ifelse(year == 2000, 1, 0)
[Your #1 above doesn't quite make sense to me: If you initialize `city' to
0, how do you condition on city == 12? Anyway, the same idea should apply:
use ifelse().]
> (3) I need the City DUmmy for the following combination: I
> have the financial flows between two cities in the state and
> I need the paired-Dummy for the exporter (state1) and
> importer (state2):
>
> g byte city11=0
> replace city11=1 if state1==12|state2==12
Seems to me that ifelse() will work here, too.
> (4) I am interesting in residuals for particular city==12. I
> have the Dummy for City==12 and regress it on Y-Variable. How
> could I extract from the output in R the residulas for
> city==12 (1) to plot this residuals and residuals from other
> regions in boxplot and (2) to etsimate the confidence interval.
Something like:
resid(regModel)[city==12]
HTH,
Andy
> Thanks very much in advice,
>
> Susan
>
>
>
>
>
>
> ---------------------------------
>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
> http://www.R-project.org/posting-guide.html
>
>
More information about the R-help
mailing list