R help - Nov 2013 - testing for bimodal and for dip in between modes in R

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 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: m66.junction.aln.pairwise.histogram.pdf
Type: application/pdf
Size: 4803 bytes
Desc: not available
URL:
<https://stat.ethz.ch/pipermail/r-help/attachments/20131124/ae8707ec/attachment.pdf>

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 <breden at sfu.ca> 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>______________________________________________
> 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.