[R] Weibull parameter estimation
Göran Broström
goran.brostrom at gmail.com
Wed Oct 22 19:57:26 CEST 2008
On Wed, Oct 22, 2008 at 1:57 PM, Borja Soto Varela <borja.soto at gmail.com> wrote:
> Dear R-users
>
> I would like to fit weibull parameters using "Method of moments" in order to
> provide the inital values of the parameter to de function 'fitdistr' . I
> don`t have much experience with maths and I don't know how to do it.
>
> Can anyone please put me in the rigth direction?
>
> Borja
>
> [[alternative HTML version deleted]]
>
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Forget the method of moments here. Reasonable starting values are
almost certainly to begin with an exponential model, i.e., give the
starting values shape = 1 and scale = mean(X), if X is your data.
This is the default behaviour of the functions phreg and aftreg in the
package 'eha'. So if you don't like to have to supply starting values,
use one of them.
--
Göran Broström
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