On May 20, 2011, at 11:45 AM, Francesco Nutini wrote:
Please forgive me for all these questions Dimitri...
I'm running these input:
mylist<-NULL #in order to hold my input
for(i in levels(mydataset$c)) { temp.data<-mydataset [mydataset$c %in
% i]
Actually looking at that the second time makes me think you might
solve the problem with a single comma.
mylist[[i]]<- lm(temp.data$a ~ temp.data$b , data=temp.data) }
That's the erros returns
Error in `[.data.frame`(mydataset, niger$site %in% i) :
"undefined columns selected"
First look:
It's possible to create factors defined that have levels with no
entries. Did you do some sub setting? Maybe you need to skip the
levels argument and instead use unique(mydataset$c), Hard to say
without your example ... which you are requested in the Posting
Guide ... to post .
Date: Fri, 20 May 2011 10:01:39 -0400
Subject: Re: [R] [r] regression coefficient for different factors
From: dimitri.liakhovit...@gmail.com
To: nutini.france...@gmail.com
CC: rb...@atsu.edu; r-help@r-project.org
First you have to create something (e.g., a list) that holds your
output:
mylist<-NULL
Then you loop through the levels of c and run a regression of a
onto b
(no need to include c anymore because c will have zero variance
within
each level of c):
for(i in levels(c)){
temp.data<-mydataset[mydataset$c %in% i]
mylist[[i]]<-lm(a ~ b, data=temp.data)
}
Once you are done - you can write another loop (this time across all
elements of mylist - that will have as many elements as there are
levels in c) and extract the coefficients.
Dimitri
On Fri, May 20, 2011 at 9:57 AM, Francesco Nutini
<nutini.france...@gmail.com> wrote:
Yes Dimitri that's what I mean!
Something like this?
for(i in levels(c)) { lm(a ~ b * c , data=mydataset)}
And what about to see the output?
Thanks!
Date: Fri, 20 May 2011 09:46:08 -0400
Subject: Re: [R] [r] regression coefficient for different factors
From: dimitri.liakhovit...@gmail.com
To: nutini.france...@gmail.com
CC: rb...@atsu.edu; r-help@r-project.org
Francesco, do you just want a separate regression for each level of
your factor c?
You could write a loop - looping through levels of c:
for(i in levels(c)){
select your data here and write a regression formula
}
On Fri, May 20, 2011 at 9:39 AM, Francesco Nutini
<nutini.france...@gmail.com> wrote:
Thanks for your reply,
?summary produce a multiple r2.
My dataset il similar to this one:
a b c
1 -1.4805676 0.9729927 x
2 1.5771695 0.2172974 x
3 -0.9567445 0.5205087 x
4 -0.9200052 0.8279428 z
5 -1.9976421 0.9641110 z
6 -0.2722960 0.6318801 y
So, I would like to know the r2 for a~b for every factors levels.
Off course I can made the regression separately for every
factors, but
my dataset have 68 factors...
----------
Francesco Nutini
PhD student
CNR-IREA (Institute for Electromagnetic Sensing of the
Environment)
Milano, Italy
From: rb...@atsu.edu
To: nutini.france...@gmail.com; r-help@r-project.org
Subject: Re: [R] [r] regression coefficient for different factors
Date: Fri, 20 May 2011 08:07:59 -0500
?summary
produces r^2 in 2nd to last line, as in,
set.seed(12); a=rnorm(100); b = runif(100); c =
factor(rep(c('No',
'Yes'),50)); df = data.frame(a,b,c)
head(df)
a b c
1 -1.4805676 0.9729927 No
2 1.5771695 0.2172974 Yes
3 -0.9567445 0.5205087 No
4 -0.9200052 0.8279428 Yes
5 -1.9976421 0.9641110 No
6 -0.2722960 0.6318801 Yes
mod = lm(a ~ b*c)
summary(mod)
Call:
lm(formula = a ~ b * c)
Residuals:
Min 1Q Median 3Q Max
-1.8196 -0.4754 -0.0246 0.5585 2.0941
Coefficients:
Estimate Std. Error t value Pr(>|t|)
(Intercept) 0.2293 0.2314 0.991 0.324
b -0.4226 0.3885 -1.088 0.280
cYes 0.1578 0.3202 0.493 0.623
b:cYes -0.5878 0.5621 -1.046 0.298
Residual standard error: 0.8455 on 96 degrees of freedom
Multiple R-squared: 0.07385, Adjusted R-squared: 0.04491
F-statistic: 2.552 on 3 and 96 DF, p-value: 0.0601
------------------------------------------
Robert W. Baer, Ph.D.
Professor of Physiology
Kirksville College of Osteopathic Medicine
A. T. Still University of Health Sciences
800 W. Jefferson St.
Kirksville, MO 63501
660-626-2322
FAX 660-626-2965
--------------------------------------------------
From: "Francesco Nutini" <nutini.france...@gmail.com>
Sent: Friday, May 20, 2011 4:17 AM
To: "[R] help" <r-help@r-project.org>
Subject: [R] [r] regression coefficient for different factors
Dear R-helpers,
In my dataset I have two continuous variable (A and B) and one
factor.
I'm investigating the regression between the two variables
usign the
command
lm(A ~ B, ...)
but now I want to know the regression coefficient (r2) of A
vs. B for
every factors.
I know that I can obtain this information with excel, but the
factor
have
68 levels...maybe [r] have a useful command.
Thanks,
Francesco Nutini
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______________________________________________
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PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible
code.
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______________________________________________
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.
--
Dimitri Liakhovitski
Ninah Consulting
www.ninah.com
--
Dimitri Liakhovitski
Ninah Consulting
www.ninah.com
[[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.
David Winsemius, MD
West Hartford, CT
______________________________________________
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.
