Excellent! Thanks for the pointer. -Ken
On 5/25/07 5:13 PM, "Marco Baroni" <[EMAIL PROTECTED]> wrote: > Dear Ken, > > Routines to fit a Zipf-Mandelbrot (probability) distribution are > implemented in our zipfR library for R: > > http://www.cogsci.uni-osnabrueck.de/~severt/zipfR > > The library documentation also points to some literature on the topic > (most notably, Baayens' 2001 Word Frequency Distributions book). > > Regards, > > Marco > > > Ken Williams wrote: >> Hi, >> >> I've got some data (picture at http://limnus.com/~ken/zipf.jpg ) that seems >> to very obviously follow a Zipf-Mandelbrot distribution, and I'm wondering >> how to best fit the parameters of the distribution given the data. >> >> I'm using the equation y = P(x + A)^-B as the canonical form of the >> Zipf-Mandelbrot curve. >> >> As a first attempt, I fixed the two endpoints (x=1 and y=1) to coincide with >> the expected values on the graph, which analytically gives me values for P >> and B as functions of A. Then I twiddle around with values for A until it >> looks nice. On the attached graph, this means I end up with A=8. >> >> This method pretty clearly overfits the endpoints, and is subject to the >> whims of my eyeballs for A. What would members of this list suggest for >> alternative fitting methods? >> >> Thanks, >> >> -Ken >> >> _______________________________________________ >> R-lang mailing list >> [email protected] >> https://ling.ucsd.edu/mailman/listinfo.cgi/r-lang >> > _______________________________________________ R-lang mailing list [email protected] https://ling.ucsd.edu/mailman/listinfo.cgi/r-lang
