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Re: st:Transformation for skewed variables with negative values?
thanks for your suggestion.
----- Original Message -----
From: "Jeph Herrin" <email@example.com>
Sent: Tuesday, August 15, 2006 9:38 AM
Subject: Re: st:Transformation for skewed variables with negative values?
> If your variables are hopelessly non-normal, you should consider converting
> them to categorical or dichotomous variables.
> Otherwise, you can transform your variables by changing the sign to reverse
> the direction of skewness and substracting (mininum-1) to make them
> strictly positive. Thus, if Y has negative skewness, -Y has positive skewness;
> and if X takes negative values, X-(min(X)-1) will be strictly positive.
> Woong.Chung@colorado.edu wrote:
> > Hello.
> > I need following help. I have panel dataset for estimating a simple linear
> > equation.
> > The problem is that my all variables have sknewness and big variation(large
> > std).
> > In particualr, the dependent variable and one of independant variables have a
> > negative sknewness, while all other independant variables are shown by positive
> > sknewness. My first intension is using a log transformation of all variables but
> > seems not to be a good idea since all variables have negative values (around
> > 20%)
> > Besides, all variables except one of independant variables are ratio, thus that
> > idea would make worse.
> > I would be so glad if anyone has suggestions to solve this problem
> > THANKS
> > WT
> > *
> > * For searches and help try:
> > * http://www.stata.com/support/faqs/res/findit.html
> > * http://www.stata.com/support/statalist/faq
> > * http://www.ats.ucla.edu/stat/stata/
> * For searches and help try:
> * http://www.stata.com/support/faqs/res/findit.html
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
* For searches and help try: