Re: [R] question from environmental statistics

From: Mike Waters <dr.mike_at_ntlworld.com>
Date: Sat 16 Jul 2005 - 21:39:19 EST


> -----Original Message-----
> From: r-help-bounces@stat.math.ethz.ch
> [mailto:r-help-bounces@stat.math.ethz.ch] On Behalf Of
> pantd@unlv.nevada.edu
> Sent: 16 July 2005 02:03
> To: r-help@stat.math.ethz.ch
> Subject: [R] question from environmental statistics
>
> thanks Fran. that was useful but Im still in a fix. its a
> real life data which looks like this:
> 0.9
> 10.9
> 24.0
> 6.7
> 0.6
> 1.0
> 2.4
> 12.4
> 7.9
> 15.8
> 1.4
> 7.9
> 11000.0
>
> (benzene conc. taken after WTC attacks)..its just a small
> chunk of data i pasted for you to look at.
> its neither normal nor lognormal. someone told me that qq
> plot does help in determining the distribution. im not sure
> how to get it.
>
> can someone help me in this.
>
> thanks
>
>
>
> Take a look at this document by Vito Ricci:
> http://cran.r-project.org/doc/contrib/Ricci-distributions-en.pdf
>
> Did you try RSiteSearch("Fit distribution") or a Google
> search? That will lead you to fit.dist{gnlm} and fitdistr{MASS}
>
> Cheers
>
> Francisco
>
>
> >From: pantd@unlv.nevada.edu
> >To: r-help@stat.math.ethz.ch
> >Subject: [R] question from environmental statistics
> >Date: Thu, 14 Jul 2005 14:06:45 -0700
> >
> >
> >
> >Dear R users
> >I want to knw if there is a way in which a raw dataset can
> be modelled
> >by some distribution. besides the gof test is there any test
> involving
> >gamma or lognormal that would fit the data.
> >
> >thank you
> >
> >-dev
>
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I think, perhaps, that we need a little more to go on, before we can help here. What do those data represent? Are they spatial (e.g. upwind versus other directions), temporal (e.g. small background values followed by an emission spike), or a combination of the two? Perhaps you have a PCB release signal superimposed on 'natural' background? In which case, maybe you want a blind signal separation procedure to separate the two as a first step.

Mike



R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Sat Jul 16 21:44:29 2005

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