rpf.prob {rpf} | R Documentation |
Map an item model, item parameters, and person trait score into a probability vector
rpf.prob(m, param, theta)
m |
an item model |
param |
item parameters |
theta |
the trait score(s) |
a vector of probabilities. For dichotomous items, probabilities are returned in the order incorrect, correct. Although redundent, both incorrect and correct probabilities are returned in the dichotomous case for API consistency with polytomous item models.
i1 <- rpf.drm() i1.p <- rpf.rparam(i1) rpf.prob(i1, c(i1.p), -1) # low trait score rpf.prob(i1, c(i1.p), c(0,1)) # average and high trait score