RE: RE: st: A bug in egen and gen?

[Maarten buis <maartenbuis@yahoo.co.uk>]

--- On Fri, 18/2/11, Liao, Junlin wrote:
> If float can indeed do the job with sufficient precision
> like everybody who tried to argue for float indicated, then
> why Stata performs its calculations with double precision?

The reason is that many statistical techniques involve a great
many computations, and a small error made many times can easily
turn out to become a big error. Ok, you might say, then why
don't I prevent a further error by storing my data as a 
double? The answer is that that way you are not preventing
an error: a float will store a variable with much more 
precision than with which it is measured, so the extra digit
you are storing contain exactly 0 information.

-- Maarten

--------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany

http://www.maartenbuis.nl
--------------------------


      

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