If I have a Uniform distribution to check, How can I use visual fits? Can I also use in some way the qqnorm?
Thanks -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Elizabeth Lawson Sent: Friday, November 18, 2005 8:06 PM To: David Zhao Cc: [email protected] Subject: Re: [R] Goodness fit test HELP! What about trying a qqplot to see how the distribution fits... For the normal distribution thta is very stright forward, use qqnorm. To test gamma distribtution (or any other) do some thing like this n<-length(data) for(i in 1:n){ prob<-(i-1/3)/(n1/3) } quantiles<-qgamma(prob,shape=mean(data)/var(data),scale=var(data)/mean(data) } qqplot(data,quantiles) If the distribution is a good for, you should a stright line, like wiht a qqnorm plot! Good luck!! Elizbaeth Lawson David Zhao <[EMAIL PROTECTED]> wrote: Hi there, I'm a newbie, plesae bear with me. I have a dataset with about 10000 ~ 30000 data points. Would like fit to both Gamma and Normal distribution to see which one fits better. How do I do this in R? Or I could do a normality test of the data, if it's normal, I then will do a normal fit, otherwise, a gamma fit. But again, I don't know how to do this either. Please help! David [[alternative HTML version deleted]] ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html --------------------------------- [[alternative HTML version deleted]] ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
