Re: [R] newbie (me) needs to model distribution as two overlapping gaussians

From: Greg Snow <Greg.Snow_at_imail.org>
Date: Tue, 19 Feb 2008 10:31:50 -0700

The mixreg package may help. Just fit an intercept only model to your data (may need to have x be a column of 1's and tell it not to include an intercept) and see if it finds your mixtures.

Hope this helps,

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow_at_imail.org
(801) 408-8111
 
 


> -----Original Message-----
> From: r-help-bounces_at_r-project.org
> [mailto:r-help-bounces_at_r-project.org] On Behalf Of tcornulier
> Sent: Monday, February 18, 2008 12:48 PM
> To: mmiller_at_mail.usp.edu
> Cc: r-help_at_r-project.org
> Subject: Re: [R] newbie (me) needs to model distribution as
> two overlapping gaussians
>
> Is a finite mixture of 2 gaussians the name you are looking for?
> This specific model will not deal with your N component however.
>
> you can find some functions here:
> http://cran.r-project.org/web/views/Cluster.html
>
> Thomas
>
> mmiller_at_mail.usp.edu wrote:
> > Recently, I have been working with some data that look like two
> > overlapping gaussian distributions. I would like to either
> >
> > 1) determine the mean and SD for each of the two distributions
> >
> > OR
> >
> > 2) get some (bayesian ?) statistic that estimates how likely an
> > observation is to belong to the left-hand or right-hand distribution
> >
> > In case I'm using the wrong language, my data looks
> something like this:
> >
> > B <- rnorm(500,40,10)
> > H <- rnorm(500,80,5 )
> > N <- runif(200,0,99)
> > D <- c(B,H,N)
> >
> > Where B=background, H=hits, N=noise, and D=my observed distribution
> >
> > I have seen analyses like this in the past, but I can't
> remember what it is called. If somebody out there can point
> me towards an R function, or even the cannonical name for
> this kind of model, I think I can write the necessary code.
> >
> > Thanks in advance,
> > Mark
> >
> > ______________________________________________
> > R-help_at_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.
> >
>
> --
>
>
> **************************
> Thomas Cornulier
>
> Mammal Research Institute
> Polish Academy of Sciences
> ul. Waszkiewicza 1c
> 17-230 Bialowieza
> http://www.zbs.bialowieza.pl/?en
>
> tel (0048) 85 682 77 88
>
> ______________________________________________
> R-help_at_r-project.org mailing list
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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.
>
______________________________________________ R-help_at_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.
Received on Tue 19 Feb 2008 - 17:46:21 GMT

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