Many thanks for your suggestions on the forum (and to those that have emailed me directly) - I'll make a start on the poisson mle approach shortly!
Paul -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Gavin Simpson Sent: 25 January 2008 15:14 To: David Winsemius Cc: [EMAIL PROTECTED] Subject: Re: [R] Poisson Maximum Likelihood Estimation >hits=-2.6 tests=BAYES_00 >X-USF-Spam-Flag: NO >On Fri, 2008-01-25 at 14:21 +0000, David Winsemius wrote: >> "Paul Sweeting" <[EMAIL PROTECTED]> wrote in >> news:[EMAIL PROTECTED]: ><snip /> >> The most straightforward approach would be to use glm() with >> family="poisson", a.k.a Poisson regression. Don't ask me why >> Gamma is capitalized as an R family but poisson is not, I don't know. >That is because there already is a gamma() for the *Gamma function*. >>From ?glm: > family: a description of the error distribution and link function to > be used in the model. This can be a character string naming a > family function, a family function or the result of a call to > a family function. (See 'family' for details of family > functions.) >So the character string must match the *name* of the correct family >function, hence you need to use "Gamma" even though you are not calling >the function directly. This isn't a string to simply say which family >you want, it has a slightly deeper meaning, hence the presumed >inconsistency. >I guess gamma() existed before the Gamma family function was included in >R or S, hence it got the lowercase name "gamma". >G ><snip /> >-- >%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% > Dr. Gavin Simpson [t] +44 (0)20 7679 0522 > ECRC, UCL Geography, [f] +44 (0)20 7679 0565 > Pearson Building, [e] gavin.simpsonATNOSPAMucl.ac.uk > Gower Street, London [w] http://www.ucl.ac.uk/~ucfagls/ > UK. WC1E 6BT. [w] http://www.freshwaters.org.uk >%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% ______________________________________________ R-help@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. ______________________________________________ R-help@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.
