Parameter estimation for Rasch type items that have never been used

Pairwise Parameter Estimation in Rasch Models

on comparing responses to pairs of items irrespective of other items. The pseudo-likelihood method is comparable to Fischer’s (1974) Minchi method. A simulation study found that the pseudo-likelihood estimates and their (estimated) standard errors were comparable to conditional and marginal maximum likelihood estimates. The method is extended to estimate parameters of the linear logistic test m...

A symbiotic view of life: we have never been individuals.

The notion of the "biological individual" is crucial to studies of genetics, immunology, evolution, development, anatomy, and physiology. Each of these biological subdisciplines has a specific conception of individuality, which has historically provided conceptual contexts for integrating newly acquired data. During the past decade, nucleic acid analysis, especially genomic sequencing and high-...

Comparison of anti-oxidant activities of seventy herbs that have been used in Korean traditional medicine

Many herbs have been used as therapeutics in Korean traditional medicine. In view of their clinical indications, anti-oxidant activity may contribute to their pharmacological effects. However, anti-oxidant information on these plants has not been available. In this study, seventy herbs which have been used in Korean traditional medicine were selected and screened for anti-oxidant activity using...

Person parameter estimation in the polytomous Rasch model

An important task in psychometric measurement is to identify the skills of persons, by accounting the difficulty degree of item responses in questionaries. The Item Response Theory (IRT) is the base for a valid measurement of the skills and the Rasch Model a well established probabilistic model, in the implementation of the theory. More recent extensions of the Rasch Model include the Partial C...

Stone tools have been used as cognitive/chronological, cultural