[R] question from environmental statistics
Mike Waters
dr.mike at ntlworld.com
Sat Jul 16 13:39:19 CEST 2005
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of
> pantd at unlv.nevada.edu
> Sent: 16 July 2005 02:03
> To: r-help at 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 at unlv.nevada.edu
> >To: r-help at 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
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