PSYCHOMETRIC ASSESSMENT OF A CHEMISTRY ACHIEVEMENT TEST AS A PREDICTOR OF ACADEMIC PERFORMANCE AMONG SENIOR SCHOOLS STUDENTS IN ONDO WEST, NIGERIA

The study assessed the psychometric of a Chemistry Achievement Test (CAT) as a predictor of academic performance among students in Ondo West secondary schools. Three research questions were raised and one hypothesis was formulated and tested at 0.05 level of significant to guide the study. The study was anchored on Item Response Theory (IRT) as the underpinning theoretical framework for modern, sophisticated test analysis and validation. The study used survey design type of descriptive research and the population comprised of chemistry students in Ondo West LGAs. One hundred and eighty students were drawn using purposive and proportionate sampling techniques. Two instruments including Chemistry Achievement Test (CAT), a 40- multiple-choice items and a secondary score data were used. The CAT’s consistency was determined using KR20 and a reliability coefficient of .74 was obtained while its accuracy was found with face and content validity methods by two psychometricians and two chemistry teachers. The psychometrics of the CAT was determined using 2-PL Model. The hypothesis formulated was tested using independent t-test. Findings revealed that 30 out of 40 items were considered suitable; Kuder–Richardson Formula 21 (KR-21) coefficient of 0.7351 suggests good internal consistency, Fisher z- test value of 2.214 is significant at the 0.05 level of significant (p