[R-sig-ME] proportions data
mikhail matz
matz at mail.utexas.edu
Tue Nov 2 18:07:57 CET 2010
Hello colleagues,
I am looking at the functional correlates of fluorescent color in the
coral larvae. My response variable ("redness") is a proportion,
ranging from about 0.5 to 0.9. The distribution of these is not very
normal, unfortunately. Arcsin-sqrt transformation does not fully
solve the problem: about a quarter of all the groups that I am
comparing still deviate from normality (lillie.test). The data tend
to be ever so slightly skewed towards larger values, but with the
sample sizes I have even a small deviation from bell-shape leads to
rejection of normality.
Is there anything I can do to be formally able to run mixed model
analysis on such data?
Misha
---------------------
Mikhail V. Matz
University of Texas at Austin
http://www.bio.utexas.edu/research/matz_lab
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