[R] weighted 2 or 3 parameter weibull estimation?
Timothy H. Keitt
tklistaddr at keittlab.bio.sunysb.edu
Fri Apr 5 17:21:19 CEST 2002
Without knowing your cost function (i.e., that passed to optim) its hard
to help.
T.
On Fri, 2002-04-05 at 02:19, Jeff D. Hamann wrote:
>
> I've figured out how to use optim (barely) to estimate 2 parameter =
> weibull distributions. I can't get over how easy this is. What I need to =
> do is use a weight in the observations.....
>
> For example,=20
>
> the tree diameters and weights are are=20
>
> 4.70 , 100
> 6.00, 98
> 7.10, 75.0
> 8.10, 86.3
> 8.60, 80.456
> 8.90, 20.5
> 9.50, 16.6
> 11.40, 12.657
> 11.80, 12.47
> 14.50, 8.98
> 16.00,4.5
> 16.90,2.36
> 18.90, 0.256
>
> which yield
>
> LOCATION =3D 0.0000 MEAN =3D 10.9921
> SCALE =3D 12.3436 VARIANCE =3D 18.0027
> SHAPE =3D 2.8050 SKEWNESS =3D 0.2354
>
> which are the values without the weights. I can't find any reference to =
> weights in the optim function and I'm afraid I'm a little stuck here. =
> After I figure out how to include the weights, I'll then need to =
> estimate the 3-parameter estimates. Any help would be greatful.=20
>
> Thanks,
> Jeff.
>
>
> Jeff D. Hamann
> Hamann, Donald & Associates, Inc.
> PO Box 1421
> Corvallis, Oregon USA 97339-1421
> Bus. 541-753-7333
> Cell. 541-740-5988
> jeff_hamann at hamanndonald.com
> www.hamanndonald.com
>
>
>
>
> -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
> r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
> Send "info", "help", or "[un]subscribe"
> (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch
> _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
More information about the R-help
mailing list