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kernel smoothing of weighted data

3 messages · riap2@cam.ac.uk, Brian Ripley, Francisco J. Zagmutt

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Hi,

I want to use kde() or a similar function for kernel smoothing but I want 
to specify the weight of each of my data points.  I do not want to specify 
the bandwidth on a point by point basis.

This seems such a simple and obvious thing to want to do I am suspicious 
that there is not an obvious way to do it.  The only discussion I have 
found is about negative weights(!) and says nothing about implementation. 
Can anyone suggest a package I have missed or suggest the best starting 
point for writing my own solution.

The reason for wanting this is that I have a number of samples each of 
~1000 data points from the same distribution but the samples are of 
slightly differing statistical weight and eventually each point in each 
sample may have its own statistical weight.

I have searched the list but I am not subscribed to it so please make me an 
addressee of any reply.

Thanks

Robert Patterson
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density() in the R-devel version of R allows weights.

locfit() in the package of the same name also appears to be documented to.
On Tue, 16 Aug 2005 riap2 at cam.ac.uk wrote:

            
The only kde() I found is from the recent package ks, and is for 
multivariate data -- if you want that, you did not say so and I've not 
looked for an answer there.

  
    
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You can also specify weights in sm.density() in the package sm.

Cheers

Francisco