Premium
A TABLE OF UPPER‐LOWER NUMBER‐RIGHT DIFFERENCE (d) AS AN INDEX OF ITEM DISCRIMINATORY POWER
Author(s) -
OLUIKPE G. C.
Publication year - 1982
Publication title -
british journal of educational psychology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.557
H-Index - 95
eISSN - 2044-8279
pISSN - 0007-0998
DOI - 10.1111/j.2044-8279.1982.tb02512.x
Subject(s) - statistics , mathematics , table (database) , rank (graph theory) , index (typography) , psychology , combinatorics , computer science , data mining , world wide web
S ummary . This paper presents a table of item discriminatory values in terms of differences in appropriate responses from equal numbers of subjects in the upper and lower tails of a distribution. The table is based on the difference between the mean scores of equal proportions taken from the opposite tails in a normal distribution. It provides separate significance values for reference with 50, 33.3 and 25 per cent of the sample taken from each tail of the distribution. It provides a means of initially classifying items as poor, fair or good, and then gives a simple method for rank‐ordering accepted items. The table requires the minimum of mathematical ability and is, therefore, recommended especially for hand computation.