Accession Number : ADA195311

Title :   Dirichlet Prior in Bayesian Estimation of Item Response Curves.

Descriptive Note : Technical rept. Jan 87-Apr 88,

Corporate Author : MISSOURI UNIV-COLUMBIA DEPT OF STATISTICS

Personal Author(s) : Tsutakawa, Robert K

PDF Url : ADA195311

Report Date : May 1988

Pagination or Media Count : 44

Abstract : This article examines the use of the ordered Dirichlet prior for binary logistic item response models. This prior is based on the investigator's prior information about the probabilities of correct response to items from examinees at several ability levels. The effect of the prior is examined in terms of the posterior mode of item parameters computed via the EM algorithm. An illustration describes the application of a 1981 ACT math test to form a prior which is used on a similar 1987 test. Detailed computational expressions for the three-parameter logistic model are summarized in an appendix. Keywords: Bayesian estimation; Item response curves.

Descriptors :   *BAYES THEOREM, *ESTIMATES, *STATISTICAL ANALYSIS, ALGORITHMS, LOGISTICS, MATHEMATICAL MODELS, PARAMETERS, RESPONSE, THREE DIMENSIONAL, DIRICHLET INTEGRAL, EXPERIMENTAL DATA

Subject Categories : Statistics and Probability

Distribution Statement : APPROVED FOR PUBLIC RELEASE