Simultaneous estimation of mean and garch eq'n

It is my experience that location parameters are not very affected
by the garch parameters.  So doing a naive estimate of location,
followed by the garch estimate, followed by an estimate of location
accounting for heteroskedasticity is likely to be indistinguishable
from the estimates from the full likelihood.

If you compare garch with the naive estimate of location versus the
garch estimate with no estimate of location, you are probably not
going to see much difference.  That difference is likely to be smaller
than if you change the time period of estimation slightly.

Patrick Burns

Burns Statistics
patrick at burns-stat.com
+44 (0)20 8525 0696
http://www.burns-stat.com
(home of S Poetry and "A Guide for the Unwilling S User")

Is it possible to simultaneously estimate mean and GARCH parameters in R?

In other words, I would like to estimate the normal regression equation

Y = b X + u

and simultaneously do a garch process on the u's to correct the 
standard errors.

I was thinking maybe something with systemfit(), but I can't quite 
come up with it.

Thanks,
    Tobias
-- 

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