[R] Adaptive kernel density was ... Fw: (no subject)

[David Winsemius]

On Jul 12, 2009, at 3:21 PM, maram salem wrote:
>
> Dear group,
> Thank u so much 4 ur help. I've tried the link,
> http://finzi.psych.upenn.edu/R/library/quantreg/html/akj.html
>
> for adaptive kernel density estimation.
> But since I'm an R beginer and the topic of adaptive estimation is  
> new for me, i still can't figure out some of the arguments of
> akj(x, z =, p =, h = -1, alpha = 0.5, kappa = 0.9, iker1 = 0)
> I've a vector of 1000 values (my X), but I don't know how to get the Z

That does seem rather trivial. According to the help page, those are  
just the points at which the density should be estimated. The example  
in the help page shows you how to create a suitable vector.

> and what's Kappa?

Not so obvious. Experimentation shows that reducing kappa makes the  
estimates less smooth.

> I'm sorry if the question is trivial but I hope u could recommend  
> some refrence if u know one.

Koenker gives two references and apparently you have some other  
material you are reading. Your university should have access to the  
Project Euclid Annals of Statistics copies that are found with the  
obvious Google search strategy.  Maybe you should be questioning the  
overall strategy of using a function you don't understand. Why, for  
instance, do you even have an interest in this function?


> Thank u so much again
> Maram
> ________________________________
> From: John Kane <jrkrideau at yahoo.ca>
>
> Sent: Monday, June 29, 2009 10:35:49 PM
> Subject: Re: [R] (no subject)
>
>
> Perhaps?
>
> http://finzi.psych.upenn.edu/R/library/quantreg/html/akj.html
>
>
>> Subject: [R] (no subject)
>> To: r-help at r-project.org
>> Received: Monday, June 29, 2009, 9:05 AM
>> Hi group,
>> I found a module for adaptive kernel density estimation for
>> Stata users, but unfortunetly I don't have access to Stata,
>> can I find a similar approach using R?
>>
>>

David Winsemius, MD
Heritage Laboratories
West Hartford, CT