Notice: On March 31, it was **announced** that Statalist is moving from an email list to a **forum**. The old list will shut down on April 23, and its replacement, **statalist.org** is already up and running.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

From |
David Hoaglin <dchoaglin@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: ladder question for right-skewed variable |

Date |
Thu, 25 Apr 2013 20:44:58 -0400 |

Gabriel, The ratio of the largest value to the smallest value is quite large, so a transformation is likely to be useful. As a first step ("first aid"), I suggest that you try the logarithm (base 10). Usually the context of the data plays a role in the choice of a transformation, so that the result is meaningful. What is the nature of disp_2000? With 1010 observations you should check whether the data has some structure (e.g., two or more modes or groups), for example, by making a histogram with a sizable number of bins (say 25 or so). If you find structure, you will need to deal with that also. David Hoaglin On Thu, Apr 25, 2013 at 8:11 PM, Gabriel Nelson <lgabrielnelson@gmail.com> wrote: > I have a variable that is right-skewed. I used the the ladder command > to see suggested transformations. However, no transformations appeared > in the output. I'm guessing that this does not mean the raw form is > better, because there is an option for 'raw' on this list. > > Here is the output for the sum, detail command for the variable: > > > > sum disp_2000, detail > > Number displaced 2000 (if data unavailable go up > to 2003 > ------------------------------------------------------------- > > Percentiles Smallest > 1% 1 1 > 5% 2 1 > 10% 3 1 Obs 1010 > 25% 6 1 Sum of Wgt. 1010 > > > 50% 15.5 Mean 281.5297 > Largest Std. Dev. 1217.168 > 75% 82 9421 > 90% 436.5 9505 Variance 1481497 > > 95% 1251 16255 Skewness 9.012044 > 99% 5953 19569 Kurtosis 108.8061 > > Any suggestions are greatly appreciated. * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: ladder question for right-skewed variable***From:*Gabriel Nelson <lgabrielnelson@gmail.com>

**Re: st: ladder question for right-skewed variable***From:*Nick Cox <njcoxstata@gmail.com>

**References**:**st: ladder question for right-skewed variable***From:*Gabriel Nelson <lgabrielnelson@gmail.com>

- Prev by Date:
**Re: st: collinearity in categorical variables** - Next by Date:
**st: Interpretation of Cut Points in Ordered Probit (Logit) Model** - Previous by thread:
**st: ladder question for right-skewed variable** - Next by thread:
**Re: st: ladder question for right-skewed variable** - Index(es):