[R] 'fitdistr' and two views of the same data?

Matt Jadud jadudm at gmail.com
Wed May 18 16:34:57 CEST 2005


I have detailed (with pictures and whatnot) my question on my weblog at 


The short version of the question is this:

When I ask 'fitdistr' to try and fit my distribution as a "weibull"
distribution, it comes up with some rather wacky parameters.

If I take the same distribution, and do something like

newdist <- mapply(function(x) ((x %/% 20) + 1), origdist)

which effectively forces the data into a histogram, 'fitdist' on
'newdist' gives me an entirely different set of parameters.
Distressingly, the parameters it gives me are, upon inspection, good;
that is, the parameters reported fit the distribution of the original
data much better than 'fitdist' of 'origdist'.

Unfortunately, I'm not savvy enough to tease this out beyond
"inspection." The weblog entry has the original distribution, plots,
and whatnot explaining my question in more detail. My question(s) are
repeated at the bottom of the post, as well as this email address. Any
help or insights are appreciated; no doubt, I've done something...
well, wrong.

Many thanks,

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