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From | Maarten Buis <maartenlbuis@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | Re: st: RE: Percentiles with basic statistics |
Date | Thu, 18 Aug 2011 16:41:06 +0200 |
On Thu, Aug 18, 2011 at 4:11 PM, Ozgur Ozdemir wrote: > I have a list of 20 variables in an excel and would like to get the mean, standard dev etc of all variables after eliminating the1% and 99% percentiles. is there any easy way of doing it rather than doing it one by one. thanks I have a number of comments: 1) We can only help you with Stata, not with excel (whatever that may be). 2) Do you want this variable by variable, or remove all observations where at least one variable satisfies your criterion? If you want to use these variables later together in an estimation command you will have to use the latter option and live with the fact that you will loose more than 2% of your observations. 3) This is a very bad idea. Outliers are the most informative observations, blindly throwing those away should (IMHO) be a crime! See: http://www.stata.com/statalist/archive/2011-08/msg00398.html Anyhow, below is an example that shows how to do this over all variables and variable by variable: *------------------------ begin example --------------------- sysuse auto, clear // store a list of all variables excluding foreign and make in // a local macro `varl' ds foreign make, not local varl `"`r(varlist)'"' // remove if at least one variable contains "outlier" gen byte touse = 1 foreach var of local varl { qui sum `var', detail replace touse = 0 if `var' <= r(p1) | ( `var' >= r(p99) & `var' < .) } // get the means and standard deviations sum `varl' if touse == 1 // remove "outlier" variable by variable foreach var of local varl { qui sum `var', detail sum `var' if `var' > r(p1) & `var' < r(p99) } *---------------- end example ----------------------- (For more on examples I sent to the Statalist see: http://www.maartenbuis.nl/example_faq ) -------------------------- Maarten L. Buis Institut fuer Soziologie Universitaet Tuebingen Wilhelmstrasse 36 72074 Tuebingen Germany http://www.maartenbuis.nl -------------------------- * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/