Item intercorrelation in the multiple-choice test
Komenda, S.
Acta Universitatis Palackianae Olomucensis Facultatis Medicae 120: 407-419
1988
ISSN/ISBN: 0301-2514 PMID: 2977918 Document Number: 311026
The test item coefficient of discrimination ability as defined by means of the coefficient of point-biserial correlation is affected by the so-called "whole-part" relation.sbd.score of the item under consideration being part of the test score. This was the reason why the relation has been studied between this coefficient with the correlation coefficient in which the adjusted test score has been taken, lowered by the respective item score. In the extensive experimental data containing 1,000 of test items the dependence has been verified of the discrimation ability coefficient of the item on its index of difficulty. Parabolic type of this dependence has been found.sbd.nevertheless, the effect of random fluctuations has been proved as significant.