Rolf, Taking out the scalar multiples did it. Thanks for that.
*Ben Caldwell* PhD Candidate University of California, Berkeley On Sun, May 15, 2011 at 10:30 PM, Rolf Turner <rolf.tur...@xtra.co.nz>wrote: > > In your example it appears that you are plotting a histogram (on the > frequency > scale) and then superimposing scalar multiples of gamma and Gaussian > densities. > > You should just plot a histogram (with frequency=FALSE) and then > superimpose the > densities --- without any scalar multipliers. > > If that doesn't work, please provide a minimal *reproducible* (no one but > you > has the ``rwb'' data object) example of the problem that you are having > (as the posting guide requests). > > cheers, > > Rolf Turner > > > > On 16/05/11 17:01, Benjamin Caldwell wrote: > > Hmm; still missing something - hist defaults to frequencies, not prob. > densities; and, I thought I'd scaled the fitted lines to the values in the > data frame. Just going with it, I specified freq=FALSE, and the prob density > was of course at a different order of magnitude than the lines. > > What are you trying to hint at? > > > On Fri, May 13, 2011 at 6:05 PM, Rolf Turner <rolf.tur...@xtra.co.nz>wrote: > >> On 14/05/11 10:00, Benjamin Caldwell wrote: >> >>> Hello, >>> >>> I'm trying to compare the fit of two distributions, normal and gamma, to >>> a >>> histogram of my response variable. >>> >>> >>> rate<-mean(na.omit(rwb$post.f.crwn.length))/var(na.omit(rwb$post.f.crwn.length)) >>> shape<-rate*mean(na.omit(rwb$post.f.crwn.length)) >>> hist((rwb$post.f.crwn.length), main="rwb$post.f.crwn.length") >>> >>> lines(seq(0.01,70,0.01),length(rwb$post.f.crwn.length)*dgamma(seq(0.01,70,0.01),shape,rate)) >>> >>> lines(seq(0,70,0.1),length(na.omit(rwb$post.f.crwn.length))*dnorm(seq(0,70,.1),mean(na.omit(rwb$post.f.crwn.length)),sqrt(var(na.omit(rwb$post.f.crwn.length)))) >>> >>> However, the height of the two curves are about 1/3 to 1/4 the height >>> that >>> they should be compared to the histogram. Any ideas? >>> >> >> Yes. Read the help on "hist"! (Hint: Pay particular attention to the >> "freq" and/or "probability" arguments.) >> >> cheers, >> >> Rolf Turner >> > > >
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