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Explaining the problem. The equating process is used to compare the scores of the two different tests with the same theme‎. ‎The goal of this research is finding the best method of equating data using Logistic model.
‎ Method. we are using the data of Ph.D‎. ‎test in Statistic major for two consecutive years 92 and 93‎. ‎For analyzing‎, ‎we are specifically using the tests of Statistics major which includes 45 questions‎. ‎Parameters of test and ability of individuals are considered according to the three parametrs model and by using the MULTILOG software‎. ‎In this study‎, ‎we are using the Mean-mean‎, ‎Mean-Sigma‎, ‎Haebara‎, ‎and Stocking-Lord methods by considering the unequal groups with Anchor-test design‎, ‎and we are using the root mean square error for choosing the optimal solution.
‎ Conclusion. The results of this study show that the methods under characteristic curve are more accurate‎.