phi2poly: Convert a phi coefficient to a polychoric correlation
Description
Given a phi coefficient (a Pearson r calculated on two dichotomous variables), and the marginal frequencies (in percentages), what is the corresponding estimate of the polychoric correlation?
Usage
phi2poly(ph, cp, cc)
Arguments
ph
phi
cp
probability of the predictor -- the so called selection ratio
cc
probability of the criterion -- the so called success rate.
Value
a polychoric correlation
Details
Uses John Fox's polycor package, which in turn requires the mvtnorm package