S3 Methods for Extracting Item Response Functions
This S3 method extracts item response functions evaluated
at a grid of abilities (skills). Item response functions can
be plotted using the IRT.irfprobPlot function.
IRT.irfprob(object, ...) ## S3 method for class 'din' IRT.irfprob(object, ...) ## S3 method for class 'gdina' IRT.irfprob(object, ...) ## S3 method for class 'gdm' IRT.irfprob(object, ...) ## S3 method for class 'mcdina' IRT.irfprob(object, ...) ## S3 method for class 'reglca' IRT.irfprob(object, ...) ## S3 method for class 'slca' IRT.irfprob(object, ...)
An array with item response probabilities (items \times categories \times skill classes [\times group]) and attributes
theta |
Uni- or multidimensional skill space (theta grid in item response models). |
prob.theta |
Probability distribution of |
skillspace |
Design matrix and estimated parameters for
skill space distribution (only for |
G |
Number of groups |
Plot functions for item response curves: IRT.irfprobPlot.
For extracting the individual likelihood or posterior see
IRT.likelihood or IRT.posterior.
## Not run: ############################################################################# # EXAMPLE 1: Extracting item response functions mcdina model ############################################################################# data(data.cdm02, package="CDM") dat <- data.cdm02$data q.matrix <- data.cdm02$q.matrix #-- estimate model mod1 <- CDM::mcdina( dat, q.matrix=q.matrix) #-- extract item response functions prmod1 <- CDM::IRT.irfprob(mod1) str(prmod1) ## End(Not run)
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