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From | Austin Nichols <austinnichols@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | Re: st: collapse and weights |
Date | Mon, 26 Nov 2012 18:36:28 +0100 |
Tomáš Houška <xbender@gmail.com>: Your goal is a bit hard to understand from the description--are you saying you want the sum of q and the q-weighted mean of price? Like: g one=1 collapse (sum) sum=one (mean) price [fweight=q], by(prod_group) On Sun, Nov 25, 2012 at 9:44 AM, Tomáš Houška <xbender@gmail.com> wrote: > Dear Statalist, > > I have data containing weekly information on prices and quantities of > sales of several products. These products can be divided into few > groups and I would like to create for each group 1) an weighted > average weekly price for the group where weight is the amounts of sale > of each product in the group and 2) sum of sales of the products that > belong to particular group. I will end up with average price and total > sales for the given product group. > > But if I use > -- collapse (sum) q (mean) price [fweight=q], by(prod_group) -- > the weights get applied both to the average and the sum, which is not > correct. I havent been able to come up with a solution how to bracket > the stata command. Could someone please give me some guidance? > Thank you! > Tomas (PhD student) * * 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/