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st: collapse with multiple sets of weights
From
"Dimitriy V. Masterov" <[email protected]>
To
Statalist <[email protected]>
Subject
st: collapse with multiple sets of weights
Date
Thu, 12 Apr 2012 11:05:34 -0400
I am trying to aggregate some spatial data. Here's a simplified
version of my problem. I have two variables, average wage and
population, in three areas. I would like to sum the population, but
calculate a weighted mean of the average wage. Is there a way to do
this in one step using collapse?
For example, the following code gets the mean right, but the population "wrong":
set obs 3;
input
pop avgwage;
10 20;
20 10;
40 30;
egen double w=total(pop);
replace w=pop/w;
collapse (sum) pop (mean) avgwage [w=w];
I would like to see 70, not 90.
Is there a collapse-like command where I apply the weight only to the
mean calculation? I suppose I could do this in two collapse steps, but
that seems clunky.
DVM
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