[R] how to change the "quantile" method in bwplot

[Matthias Kohl]

for teaching purposes I wrote a corresponding function; cf.
qbxp.stats (as well as qboxplot ...) in package MKmisc.

hth,
Matthias

Deepayan Sarkar schrieb:
> On Tue, Jul 21, 2009 at 7:47 AM, Jun Shen<jun.shen.ut at gmail.com> wrote:
>   
>> Uwe,
>>
>> Thank you for your reply.  I am still not very clear about the meanings of
>> the arguments in the stats function.   To make it clearer, quantile() uses
>> type=7 as default method. I believe this is the method bwplot() uses to
>> calculate the quantiles. I want to use type=6 method for bwplot(). How do I
>> achieve that? Thanks again.
>>     
>
> Maybe this will be clearer: bwplot() uses the boxplot.stats() function
> to compute the "quantiles" used, which in turn uses fivenum(), which
> has its own quantile calculation (and does not explicitly use
> quantile()). There is no easy way to allow for type=6 etc. here.
>
> bwplot() allows you to replace boxplot.stats() and provide your own
> alternative. So what you need to do is:
>
> (1) write a function, say, 'my.boxpot.stats', that takes the same
> arguments as boxplot.stats() and returns a similar result, but using
> your preferred calculation for the quantiles. There are many ways to
> do this.
>
> (2) plug in this function into the bwplot() call; e.g. bwplot(...,
> stats = my.boxplot.stats)
>
> -Deepayan
>
>
>   
>> Jun
>>
>> 2009/7/21 Uwe Ligges <ligges at statistik.tu-dortmund.de>
>>
>>     
>>> Jun Shen wrote:
>>>
>>>       
>>>> Hi, everyone,
>>>>
>>>> Since quantile calculation has nine different methods in R, I wonder how I
>>>> specify a method when calling the bwplot() in lattice. I couldn't find any
>>>> information in the documentation. Thanks.
>>>>
>>>>
>>>>         
>>> bwplot() uses the panel function panel.bwplot() which allows to specify a
>>> function that calculates the statistics in its argument stats that defaults
>>> to boxplot.stats(). Hence you can change that function.
>>>
>>> Example with some fixed values:
>>>
>>> bwplot( ~ 1:10,
>>>    stats = function(x, ...)
>>>        return(list(stats=1:5, n=10, conf=1, 10, out=integer(0)))
>>> )
>>>
>>>
>>> Uwe Ligges
>>>
>>>       
>>        [[alternative HTML version deleted]]
>>
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>> and provide commented, minimal, self-contained, reproducible code.
>>
>>     
>
> ______________________________________________
> 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.
>   

-- 
Dr. Matthias Kohl
www.stamats.de