testing for bimodal and for dip in between modes in R

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testing for bimodal and for dip in between modes in R

Felix Breden
Hi
I have distributions that are typically bimodal (see attached .pdf), and I would like to test for bimodality, and then estimate the point between the two modes, the dip in the distributions. any help would be greatly appreciated.
thanks
felix
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m66.junction.aln.pairwise.histogram.pdf (6K) Download Attachment
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Re: testing for bimodal and for dip in between modes in R

szehnder@uni-bonn.de
Testing for bimodality is rather testing for unimodality. Hartigan and Hartigan (1985) presented the Dip-Test which is implemented in the R package DipTest with a much better approximation of the test distribution. If the test statistic is too high unimodality is rejected. To estimate the dip point you could choose among several possibilities: (1) A very easy method is to use the kmeans function for a kmeans cluster and use the point in the middle of the connecting line between the kmeans cluster centers. (2) You could estimate a finite mixture distribution and take the middle of the connecting line of the modes.

Best

Simon
 
On 24 Nov 2013, at 20:41, Felix Breden <[hidden email]> wrote:

> Hi
> I have distributions that are typically bimodal (see attached .pdf), and I would like to test for bimodality, and then estimate the point between the two modes, the dip in the distributions. any help would be greatly appreciated.
> thanks
> felix <m66.junction.aln.pairwise.histogram.pdf>______________________________________________
> [hidden email] 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.

______________________________________________
[hidden email] 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.