Fitting Test for Logistic Function in Defining the Ability Level and Ranking in Exams

In this paper with using the three- parameter logistic function in response to 4  choice items, the range of ability of each participant for each item or each exam is measured by Item response theory (IRT) and is marked and ranked by each participant’s ability. We will compare (IRT) with traditional ways of marking and ranking, with fitting tests. For this purpose we used IRT and many softwares that we created ourselves for marking one of the exams of the Educational Assessment of Iran (sanjesh.org) and finding each participant’s ranking.