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The present Study aimed to investigate whether one of the [RT models tit the data obtained from ÖZDEBlR ÖSS Exam mathematics Subtest and distinguish the lRT model thatfıts well to the data. Data was derived randomly from sxaminees throughout _ Gnodness of rit investigations were done through examination of unidimcnsionŞlMy,V local] independenca equal discrimination indices, minimal guessing, non SpCCdcd test administration invariance of ability parameter estimates and invarinnee of item parameter estimates. ln addition. item lllflll'n'lftliüll functions and iten] characteristics curves were reviewed. Results presented that the most appropriate model data tit was achieved by “ “LM