IRT.frequencies: S3 Method for Computing Observed and Expected Frequencies of...

In CDM: Cognitive Diagnosis Modeling

S3 Method for Computing Observed and Expected Frequencies of Univariate and Bivariate Marginals

Description

This S3 method computes observed and expected frequencies for univariate and bivariate distributions.

Usage

IRT.frequencies(object, ...)

IRT_frequencies_default(data, post, probs, weights=NULL)

IRT_frequencies_wrapper(object, ...)

## S3 method for class 'din'
IRT.frequencies(object, ...)

## S3 method for class 'gdina'
IRT.frequencies(object, ...)

## S3 method for class 'mcdina'
IRT.frequencies(object, ...)

## S3 method for class 'gdm'
IRT.frequencies(object, ...)

## S3 method for class 'slca'
IRT.frequencies(object, ...)

Arguments

object	Object of classes din, gdina, mcdina, gdm or slca.
...	More arguments to be passed.
data	Item response data as extracted by IRT.data
post	Individual posterior distribution as extracted by IRT.posterior
probs	Individual posterior distribution as extracted by IRT.irfprob
weights	Optional vector of weights as included as the attribute weights in IRT.data

Value

List with following entries

uni_obs	Univariate observed distribution
uni_exp	Univariate expected distribution
M_obs	Univariate observed means
M_exp	Univariate expected means
SD_obs	Univariate observed standard deviations
SD_exp	Univariate expected standard deviations
biv_obs	Bivariate observed frequencies
biv_exp	Bivariate expected frequencies
biv_N	Bivariate sample size
cov_obs	Observed covariances
cov_cor	Expected covariances
cor_obs	Observed correlations
cor_exp	Expected correlations
chisq	Chi square statistic of local independence

Examples

## Not run: 
#############################################################################
# EXAMPLE 1: Usage IRT.frequencies
#############################################################################

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

# estimate GDINA model
mod1 <- CDM::gdina( data=sim.dina,  q.matrix=sim.qmatrix)
summary(mod1)

# direct usage of IRT.frequencies
fres1 <- CDM::IRT.frequencies(mod1)

# use of the default function with input data
data <- CDM::IRT.data(object)
post <- CDM::IRT.posterior(object)
probs <- CDM::IRT.irfprob(object)
fres2 <- CDM::IRT_frequencies_default(data=data, post=post, probs=probs)

## End(Not run)

CDM documentation built on Aug. 25, 2022, 5:08 p.m.