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Re: st: Standard error of a sum
Meloria Meschi wrote:
> I have a silly problem that's driving me nuts. I have estimated two
> production function, with AR(1) correction. I got 7 point forecasts each
> and their standard errors (call each forecast series x1 and x2). I have
> computed the confidence intervals for each of these forecasts.
> Then I have added the two forecasts into one series y=x1 + x2 and produced
> s.e. and confidence intervals for this series as well. What I need now is
> a confidence interval for the sum of y (ie total production from the two
> sites). How do I compute the standard error for this total? And does it
> actually make sense to do so?
. summarize y, display
tell you? I'm assuming these functions are continuous, valid measurements
which have no bounds. If so, calculating standard errors should pose no
difficulties. But only _you_ can answer that question!
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