phi2poly {psych} | R Documentation |
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?
phi2poly(ph, cp, cc)
ph |
phi |
cp |
probability of the predictor – the so called selection ratio |
cc |
probability of the criterion – the so called success rate. |
Uses John Fox's polycor package, which in turn requires the mvtnorm package
a polychoric correlation
William Revelle
#phi2poly(.3,.5,.5) #phi2poly(.3,.3,.7)