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Re: st: Inverse hyperbolic sine function


From   Ricardo Ovaldia <ovaldia@yahoo.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Inverse hyperbolic sine function
Date   Thu, 31 Mar 2005 09:22:51 -0800 (PST)

--- smerryman@kc.rr.com wrote:
> 1.  Yes, but more generally, the ihs fuctions is
> ln(theta*z + sqrt((theta^2 * z^2
>  + 1))/theta; where theta is scale parameter that
> could be estimated.

Is IHS = log(z + sqrt(z^2 + 1)) then only an
approximation? If so, I assume that it is good when z
is large relative to 1/theta. But how can we know
ahead of time how good the approximation will be on
our data?

Regards,
Ricardo.
 


		
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