On Thu, May 21, 2009 at 12:21 PM, Claire Terhune <[email protected]
<mailto:[email protected]>> wrote:
Hello all-
I need a bit of assistance with interpreting the results of my
2B-PLS analyses. I am looking at the covariance between two curves
with the same number of points and specimens (15 2D pts and 45
specimens). I first slid the landmarks in tpsrelw, and then took the
aligned coordinates and performed 2B-PLS analyses in tpsPLS and in
MorphoJ, simply to compare the results. Generally, the values that
both programs return are the same, but I’m unsure of the
significance of the results since they seem to differ substantially.
In TPS, the observed correlation for dimension 1 is 0.912348, and
the permutation test (1000 iterations) indicates that no permuted
values exceeded the test value, which (if I am interpreting this
correctly) should indicate a p-value of <0.001 for that dimension.
In MorhoJ, I get the same general correlation value (0.91225) for
the first dimension, but the permuted p-value (also from 1000
iterations) is 0.6290 (although the reported p-value for the
singular value for the same dimension is <0.001).
Given that the correlation is so high, it would surprise me if the
p-value was not significant, particularly since the RV coefficient
reported by MorphoJ is 0.7537 with a permuted p-value of <0.001.
I must be misinterpreting something here, but I’m not sure what
exactly that is, so any help that could be provided would be greatly
appreciated!
Thanks,
Claire
--
Claire E. Terhune
Ph.D. Candidate
School of Human Evolution
and Social Change
Arizona State University
PO Box 872402
Tempe, AZ 85287-2402
[email protected] <mailto:[email protected]>
--
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