Calculate3plProb {DFIT}

Calculates the item success probability under the 3PL model.

Description

Calculates the item success probability under the 3PL model.

Usage

Calculate3plProb(thetaValue, itemParameters, logistic = TRUE)

Arguments

thetaValue

A numeric value or array for the theta (ability) value(s) where the difference will be calculated

itemParameters

A matrix containing the numeric values of item discriminations on the first column, item difficulties on the second and item guessing parameters on the third

logistic

A logical value stating if the IRT model will use the logistic or the normal metric.

Value

probabilities A numeric matrix with the probabilities on each thetaValue for each item.

Author(s)

Victor H. Cervantes <vhcervantesb at unal.edu.co>

References

de Ayala, R. J., (2009). The theory and practice of item response theory. New York: The Guildford Press