CDM (version 7.4-19)

IRT.expectedCounts: S3 Method for Extracting Expected Counts

Description

This S3 method extracts expected counts from model output.

Usage

IRT.expectedCounts(object, ...)
# S3 method for din
IRT.expectedCounts(object, …)
# S3 method for gdina
IRT.expectedCounts(object, …)
# S3 method for gdm
IRT.expectedCounts(object, …)
# S3 method for mcdina
IRT.expectedCounts(object, …)
# S3 method for slca
IRT.expectedCounts(object, …)
# S3 method for reglca
IRT.expectedCounts(object, …)

Arguments

object

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

…

More arguments to be passed.

Value

An array with expected counts. The dimensions are items, categories, latent classes and groups.

Examples

# NOT RUN {
#############################################################################
# EXAMPLE 1: Expected counts gdm function
#############################################################################

data(data.fraction1, package="CDM")
dat <- data.fraction1$data
theta.k <- seq( -6, 6, len=11 )   # discretized ability

#--- Model 1: Rasch model
mod1 <- CDM::gdm( dat, irtmodel="1PL", theta.k=theta.k, skillspace="normal",
               centered.latent=TRUE )
emod1 <- CDM::IRT.expectedCounts(mod1)
str(emod1)

#############################################################################
# EXAMPLE 2: Expected counts gdina function
#############################################################################

data(sim.dina, package="CDM")
data(sim.qmatrix, package="CDM")

#--- Model 1: estimation of the GDINA model
mod1 <- CDM::gdina( data=sim.dina, q.matrix=sim.qmatrix)
summary(mod1)
emod1 <- CDM::IRT.expectedCounts(mod1)
str(emod1)

#--- Model 2: GDINA model with two groups
mod2 <- CDM::gdina( data=CDM::sim.dina, q.matrix=CDM::sim.qmatrix,
                   group=rep(1:2, each=200) )
summary(mod2)
emod2 <- CDM::IRT.expectedCounts( mod2 )
str(emod2)
# }