Dear list,
I am trying to standardise independent contrasts following Garland et
al. (1992), but I am unsure just how you would extract the sum of it's
[contrast's] branch lenghts in R.
I computed independent contrasts using the pic function in ape. I
then took the contrasts and subtracted the
The contrasts returned by pic() should already be standardized.
Standardizing phylogenetic contrasts is performed by dividing each
contrast (calculated between internal or terminal nodes) by a sum
proportional to the square root of its expected variance. Assuming
Brownian motion, for two
