[R] Help with Beta Distribution

[A.J. Rossini]

>>>>> "TR" == Tharacad Ramanarayanan <Tharacad.Ramanarayanan at aventis.com> writes:

    TR> First let me confess that I am a R-novice.  I am trying to fit
    TR> a beta distribution for a dataset using fitdistr(MASS). I am
    TR> having difficulties with it because the function tends to fit
    TR> a distribution with a range of 0 to 1 (I guess). However, my
    TR> dataset is not!

    TR> Since a beta (range in 0,1) doesn't describe what you want,
    TR> why force it?

    TR> Hmm . . . a standard beta distribution(B(x)) is 0 < x < 1. So
    TR> is a standard uniform distribution. A standard beta
    TR> distribution can be transformed for any (positive) range.

Right - so did you transform your data back (or rewrite the
distribution forward)?

It does work when everything is on the same scale.

best,
-tony

-- 
A.J. Rossini				Rsrch. Asst. Prof. of Biostatistics
U. of Washington Biostatistics		rossini at u.washington.edu	
FHCRC/SCHARP/HIV Vaccine Trials Net	rossini at scharp.org
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