[R] Density estimation

[Greg Snow]

Look at the logspline package.  It has a different way of estimating
densities that allows for limits to be specified (i.e. probability is 0
beyond the point(s) you specify).

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 Gunther Jansen
> Sent: Wednesday, April 23, 2008 4:59 AM
> To: r-help at r-project.org
> Subject: [R] Density estimation
> 
> Hi,
> 
> I am analysing a dataset containing genetic distances within 
> and between species. I want to show a overlap of the 
> distributions of the intra- and interspecific values; on a 
> second graph I use a cut-off value to determine these 
> boundaries. As the dataset contains >30 000 values, I would 
> like to do this with a simple line rather than superimposed 
> histograms. Hence, density plots. With the standard settings 
> of plot(density(x)), I receive the desirable result, except 
> that the function extends slightly in negative x values 
> (which is impossible, distance values are always positive). 
> Furthermore, in the second figure I supplied the cut-off 
> value a priori, so overlap between the two classes is zero by 
> definition. Is there a way to visualise this information in 
> another way, or to readjust the density parameters so 
> intraspecific values below zero have zero probability in the 
> first case, and there is no overlap in the second case?
> 
> 
> Thanks,
> 
> gunther
> 
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