[R] negatively skewed data; reflecting

[Eik Vettorazzi]

a simple reflection (on the y-axis) of x is -x, but you have to ensure  
that there are only nonnegative numbers if you want to use the log  
transformation. So you should reflect on a postive number z greater than  
abs(min(x)), if min(x)<0. This is done by z-x.
Why don't you simply shift your data by this amount z or use a  
box-cox-transformation at all?

Am Wed, 23 Aug 2006 14:08:08 +0200 schrieb <z.dalton at lancaster.ac.uk>:

> Hi,
>
> This problem may be very easy, but I can't think of how to do it.  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?  I'm  
> sorry if this seems a very simple task, I think it involves going back  
> to Maths GCSE and relearning reflection, rotation, translation etc!  I  
> have searched the internet, but cannot come up with anything useful on  
> how to reflect data.
>
>> hist(Lsoc)  #how do I reflect Lsoc in R?
>
> I am grateful for any help regarding this matter, it is just a very  
> small part of my analysis and doesn't seem worth agonising hours over.   
> I will probably kick myself when someone tells me the answer!
>
> Thank you very much,
>
> Zoe
>
> ______________________________________________
> R-help at stat.math.ethz.ch 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.
>