Rasch Calibration of General Science Test at Grade-VIII in Pakistan

The present study aimed at calibration of General Science achievement test for grade (VIII) through Rasch Model. For this purpose a General Science achievement test comprising 45 items was constructed from the text book of General Science for class VIII. Finally the test was administered to 300 students (M/F) in different high schools for boys and girls in Multan District. The answer sheets were scored and results were tabulated. Eleven (11) items were rejected on the basis of F, D and. Fifteen (15) items were to be improved on the basis of F, D. Remaining all items were good items. Rasch Model indicates that overall test is good to measure the achievement of the students class (VIII) in the subject of General Science. On the basis of findings, major conclusions were drawn: One item was rejected on the basis of facility index (F). Twelve (12) items need improvement on the basis of facility index (F). Thirty two (32) items were very good items on the basis of facility index (F). Seven items were rejected on the basis of discrimination index (D). One item needed improvement on the basis of discrimination index (D). Thirty seven (37) items were good items on the basis of discrimination index (D). Three items were rejected on the basis of phi-co-efficient. Two items needed improvement on the basis of phi-co-efficient. Forty items were good on the basis of phi-coefficient. Test has high positive test reliability value.22 distracters were to be rejected as attempted by less than 5%.The distracters D(27), B(28), A(31), D(37), B(41), A(43) and B(10) were distracters attracted by high achievers more than low achievers, so they were rejected.