关键词: 项目反应理论, 数学模型, 参数估计, 样本容量, 拟合性检验

Abstract: The study focused on the selections to mathematical models of item response theory, and fitting tests of mathematical models. relations between the sample size and item reponse models, and relations between the sample size and pararnaters estimation of item response models. All the data the study adopted came from the National College Entrance Examination. The study has come to some significant conclusions.

Key words: item response theory, mathematical models, estimation of parameters, sample size, fitting test