RESEARCH ON SIMULATE TRIAL FOR THE OPTIMALMATCH BETWEEN THE DISTRIBUTION OF ABILITY ANDTHE DISTRIBUTION OF ITEM DIFFICULTY
项目难度与被试能力分布最优匹配的模拟研究

This research explored optimal match between distribution of the examinees ability and distribution of the items ' difficulty by Monte Carlo Simulate Approach. The results showed that when the distribution of the examinees ' ability were standard normal, positive skewness or negative skewness and the distribution of items ' difficulty were the same as ability distribution respectively, the indices of match, such as the expected information function value, maximum information function value and reliability were higher than the other match indices. The accuracy was also higher than the other match in estimating item difficulty, discrimination and examinees ' ability.