Re: [R] about Cox-Box transformation

From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>
Date: Thu 09 Feb 2006 - 23:59:15 EST

On Thu, 9 Feb 2006, Petr Pikal wrote:

> Hi
>
> 1. upgrade
> 2. read Introduction to R shipped with the distribution
> 3. read documentation to MASS
> 4. packages not libraries
> 5. use library(MASS) to make functions from MASS package available
> 6. now you can use boxcox() but not on vectors AFAIK

You can by

boxcox(y ~ 1)

but car's box.cox does similar things. (I did not mention that as adding packages to R 1.8.0 is unlikely to be easy.)

> probably not completely correct but this
>
> box.cox <- function(x, lambda,inv=F)
> { if (!inv)
> {if(missing(lambda))
> log(x)
> else (x^lambda - 1)/lambda}
> else (lambda*x+1)^(1/lambda)
> }
>
> you can use to perform Box-Cox transformation on vectors.
>
> HTH
> Petr
>
>
> On 9 Feb 2006 at 11:51, Stefano Sofia wrote:
>
> From: Stefano Sofia <stefano.sofia@regione.marche.it>
> To: r-help@stat.math.ethz.ch
> Date sent: Thu, 09 Feb 2006 11:51:02 +0000
> Subject: [R] about Cox-Box transformation
>
>> Dear R-users,
>> I am using R version 1.8.0-1 under Suse 8.2.
>> I need to use the boxcox command because I want to apply a Cox-Box
>> transformation to a vector of rainfall values. Within the libraries,
>> the MASS library is present, but I don't know whether this means that
>> is automatically installed or not. The command doesn't work. What do I
>> have to do in order to make it working? Is just a problem of
>> installation or simply of recalling the right command?
>>
>> thank you for your help
>> Stefano

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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Received on Fri Feb 10 00:10:37 2006

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