[R] negatively skewed data; reflecting

[Michael Kubovy]

On Aug 23, 2006, at 8:08 AM, z.dalton at lancaster.ac.uk wrote:

> I have constructed histograms of various variables in my dataset.   
> Some of them are negatively skewed, and hence need data  
> transformations applied.  I know that you first need to reflect the  
> negatively skewed data and then apply another transformation such  
> as log, square root etc to bring it towards normailty. How is it  
> that I reflect data in R?
>
>> hist(Lsoc)  #how do I reflect Lsoc in R?

To reflect the vector Lsoc, assuming the numbers are positive, and  
keep them positive in order to take (e.g.) logs,
log(-Lsoc + max(Lsoc) + 1).

But if you do a Google search on 'ladder powers negative skew' you'll  
find another answer. The idea of the ladder of powers is due to J W  
Tukey.
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