16 Pages

J. Implementation of Estimation for Mixed Models

In order to illustrate estimation of item parameters in the mixed models, a BASIC computer program was developed. The computer program, based on marginal maximum likelihood estimation of Bock and Aitkin (1981), has been written specifically to handle contrived data consist of three dichotomouslyscored items and two polytomously-scored items. The two-parameter logistic model and the logistic form of the graded response model are used for parameter estimation.