Doh! Really should have remembered that,
likelihoods-can-be-greater-than-1 is likelihood 101...
I am still a little puzzled by the dramatically different
results between rescaling and not, will try to post an
example in a sec...
On 3/7/11 12:37 PM, Nick Matzke wrote:
Hi all,
It seems to be a popular week for questions!
I am running fitContinuous on a variety of continuous trait
data. I am noticing that when the traits are in units where
the max is less than 1 (these are not ratio data, though),
many of the various models produce log-likelihoods that are
positive, which ought to be impossible.
If I rescale the trait values, e.g. by multiplying them by
100, the problem goes away and all log-likelihoods are
negative, and come out somewhat similar to each other
between the BM, OU, etc. models, as one would expect.
Any hint about why this might be?
Cheers,
Nick
--
====================================================
Nicholas J. Matzke
Ph.D. Candidate, Graduate Student Researcher
Huelsenbeck Lab
Center for Theoretical Evolutionary Genomics
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University of California, Berkeley
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When people thought the earth was spherical, they were
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