On Thu, 25 Aug 2005, Prof Brian Ripley wrote: > On Thu, 25 Aug 2005, Mark Miller wrote: > >> I am trying to fit a number of distributions to a set of data, I have used >> the >> fitdristr() funtion for most of the distributions, but Poisson is not one >> of >> the possible distributions. I found somewhee talking about using the gamlss >> package, but have been unable to find it again, any help would be greatly >> appreciated. > > If you mean fitdistr in package MASS, it can be used. But the mle for a > Poisson is just the sample mean. > >> x <- rpois(250, 2.6) >> mean(x) > [1] 2.62 >> fitdistr(x, dpois, list(lambda=2)) > lambda > 2.6203125 > (0.1023841) > > You can even find the s.e. via mu/sqrt(n), here >> mean(x)/sqrt(250) > [1] 0.1657033
Sorry, sqrt(mu/n). -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html