Accession Number:

ADA179215

Title:

Estimation for the Rasch Model When Both Ability and Difficulty Parameters are Random.

Descriptive Note:

Technical rept. 1 Jan 85-31 Dec 86,

Corporate Author:

MISSOURI UNIV-COLUMBIA DEPT OF STATISTICS

Report Date:

1987-02-01

Pagination or Media Count:

33.0

Abstract:

Estimation of the parameters of the Rasch model, a one parameters item response model, is considered when both the item parameters and the ability parameters are considered random quantities. It is assumed that the item parameters are drawn from a Ngamma tau to the 2nd power distribution, and the abilities are drawn from a Nomicron, sigma to the 2nd power distribution. A variation of the EM algorithm is used to find approximate maximum likelihood estimates of gamma, tack and sigma. A second approach assumes that the difficulty parameters are drawn from a uniform distribution over part of the real line. Real and simulated data sets are discussed for illustration. Keywords Statistical data TablesData.

Subject Categories:

  • Statistics and Probability

Distribution Statement:

APPROVED FOR PUBLIC RELEASE