I mentioned earlier the alternative of having two-state discrete
characters each modeled by an underlying quantitative character with a
developmental threshold.
This can in principle be extended to three or more states. In fact,
Sewall Wright's original example in 1934 had three states. But
Dear all,
(apologies for multiple posting)
On behalf of the apex development team (E. Paradis, K. Schliep, Z. Kamvar, R.
Harris and myself), I am happy to announce that apex has been released on CRAN:
http://cran.r-project.org/web/packages/apex/index.html
This package provides tools for
