help error: In dweibull(x, shape, scale, log) : NaNs produzidos
I haven't quite worked it out for the Wiebull but that will certainly (down-) bias your variance estimates for, e.g., the normal. I think the right thing to do is to use the correct distribution rather than forcing an incorrect distribution to fit incorrectly. Michael
On Feb 21, 2012, at 1:10 PM, Van?cia Schumacher<vanucia-schumacher at hotmail.com> wrote:
Hi, then, If I replace the midpoint 0.0025 average values equal to 0there won't be prejudice in the results?Would then be the best thing to do? regards,
Subject: Re: [R] help error: In dweibull(x, shape, scale, log) : NaNs produzidos From: pdalgd at gmail.com Date: Tue, 21 Feb 2012 18:55:51 +0100 To: vanucia-schumacher at hotmail.com On Feb 21, 2012, at 18:34 , Van?cia Schumacher wrote:
Thank's, but then I could simply round off my data which are equal to zero to 0.00001?
Something like that. I'd maybe try something a little more carefully considered. E.g. if your data are rounded to two decimal figures, the "zeros" represent values of x with 0 < x < 0.005 since anything bigger would be rounded to 0.01. So replace with the interval midpoint of 0.0025. (One can do better by modifying the likelihood, but then you essentially have to rewrite fitdistr().)
Att, Van?cia Schumacher Curso de gradua??o em meteorologia - UFPEL Bolsista do Programa de Educa??o Tutorial - PET
Subject: Re: [R] help error: In dweibull(x, shape, scale, log) : NaNs produzidos From: pdalgd at gmail.com Date: Tue, 21 Feb 2012 17:43:07 +0100 CC: vanucia-schumacher at hotmail.com; r-help at r-project.org To: dwinsemius at comcast.net On Feb 21, 2012, at 16:36 , David Winsemius wrote:
It suggests you managed to send negative or infinite numbers to dweibull, a distribution which only supports values when given positive, finite numbers. Look at your data more closely.
Zeros are a common cause, too. For a < 1 (the shape parameter), the Weibull density has a singularity at zero, and fitdistr() is not tolerant of observations rounded to zero in such cases. -- Peter Dalgaard, Professor Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com
-- Peter Dalgaard, Professor Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com
[[alternative HTML version deleted]]
______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.