subjOCCDIF {KernSmoothIRT}

ksIRT - kernel smoothing in Item Response Theory

Description

Applies only when the groups argument is specified. It returns a list containing a matrix for each item for each of the different groups. Each matrix in the list contains a row for each option with each column representing a subject with the probability of selecting that option for each subject.

Usage

subjOCCDIF(x, stype = c("ObsScore","Theta","ThetaML","ScoreML"))

Arguments

x

a ksIRT object to be analyzed.

stype

the scale on which to evaluate each subject. stype = "ObsScore" uses the subject's total score. stype = "Theta" uses the subject's rank on the thetadist scale. stype = "ThetaML" uses the maximum likelihood estimate for the subject on the thetadist scale. codestype = "ScoreML" uses the maximum likelihood estimate for the subject on the overall test score scale.

References

Ramsay, J.O. (2000). TestGraf: A program for the graphical analysis of multiple choice test and questionnaire data.

Silverman, B.W. (1986). Density Estimation for Statistics and Data Analysis. Chapman & Hall, London.