You can use rgamma to get a gamma distribution for use in qqplot, eg : x <-rchisq(100,2) y<- fitdistr(x,"gamma")
qqplot(rgamma(100,y$estimate[1],y$estimate[2], x) Cheers Joris On Wed, Jun 16, 2010 at 9:40 AM, Marcosco01 <marco.scortich...@bancamarche.it> wrote: > > I'm looking for goodness of fit tests for gamma distributions with large data > sizes and for different data. > I have a matrix with around 4.000 data values in it and i have fitted a > gamma distribution with "fitdistr". > > You can see the example: > >> fitdistr(corpo,"gamma",lower=0.001) > > Errore in optim(x = c(5000, 5000, 5000, 5000, 5000, 5000, 5000, 5000, > 5000, : > non-finite finite-difference value [2] > > The problem is the optimization for the test with different data and for the > size larger than 516 data. > > in summary > -is there a gamma goodness of fit test that doesnt depend on the sample > size? > -is there a way of using qqplot for gamma distributions, if so how would you > calculate it from a matrix of data values? > > -- > View this message in context: > http://r.789695.n4.nabble.com/Fitting-Gamma-distribution-tp2257014p2257014.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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. > -- Joris Meys Statistical consultant Ghent University Faculty of Bioscience Engineering Department of Applied mathematics, biometrics and process control tel : +32 9 264 59 87 joris.m...@ugent.be ------------------------------- Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php ______________________________________________ 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.