Investigation of quantitative ability difference based on gender: A differential item functioning(DIF) study

At this thesis study, the differentiation in quantitative ability between sexes is studied. For this, first of all, a test is formed that is totally 40 items each of which has sub-tests composed of 10 items. The test was applied to 400 sample students that were 11th class in 2017-2018 educational year. After the applicationitem selection was made by accounting item difficulties and item discrimination parameters. Studies for reliability and validity were made, 5 items from each that best measure the subject structures(arithmetical reasoning, forming equality, geometry, visual-spatial ability) were chosen and the final form of the test was decided. After that the test was applied to 1382 students who attend 11th class in 2018-2019 at Bornova Anadolu, Cihat Kora Anadolu, 15 Temmuz Şehitler Anadolu, Atatürk Lisesi, Karşıyaka Lisesi and Atakent Anadolu high schools. After making necessary eliminations, series of analysis were made for a sample of 1036 students. Items which differ according to sexes are confirmed. It has been found out that within the items which display Differential Item Function(DIF), two items that are related to forming equality and arithmetical reasoning are in favor of boys where three items that are related to geometry and visual spatial ability are in favor of girls. On the other hand, the quantitative ability test (QAT) mentioned was checked in means of concordance with Rasch model and was reported. It has been seen that all items except one fit well with the model, data-model, person-model and test-model fits are good, and meet local independency and unidimensionality assumptions hypothesis. Key words: Quantitative Ability Test(QAT), Rasch Model, Differential Item Function(DIF)