CDM (version 4.991-1)

IRT.likelihood: S3 Methods for Extracting of the Individual Likelihood and the Individual Posterior

Description

Functions for extracting the individual likelihood and individual posterior distribution.

Usage

IRT.likelihood(object, ...)
IRT.posterior(object, ...)
"IRT.likelihood"(object, ...)
"IRT.posterior"(object, ...)
"IRT.likelihood"(object, ...)
"IRT.posterior"(object, ...)
"IRT.likelihood"(object, ...)
"IRT.posterior"(object, ...)
"IRT.likelihood"(object, ...)
"IRT.posterior"(object, ...)
"IRT.likelihood"(object, ...)
"IRT.posterior"(object, ...)

Arguments

object

Object of classes din, gdina, mcdina, gdm or slca.

...

More arguments to be passed.

Value

For both functions IRT.likelihood and IRT.posterior, it is a matrix with attributes

theta

Uni- or multidimensional skill space (theta grid in item response models).

prob.theta

Probability distribution of theta

skillspace

Design matrix and estimated parameters for skill space distribution (only for IRT.posterior.slca)

G

Number of groups

Examples

#############################################################################
# EXAMPLE 1: Extracting likelihood and posterior from a DINA model
#############################################################################

data(sim.data)
data(sim.qmatrix)

#*** estimate model
mod1 <- din(sim.dina, sim.qmatrix, rule = "DINA" , maxit=10)
#*** extract likelihood
likemod1 <- IRT.likelihood(mod1)
str(likemod1)
# extract theta
attr(likemod1, "theta" )
#*** extract posterior
pomod1 <- IRT.posterior( mod1 )
str(pomod1)