Osadebe Patrick U
Patrick U. Osadebe, P. O. Box 88, Obiaruku, Delta State University, Abraka, Nigeria,
J Appl Meas. 2018;19(1):106-112.
The study was carried out to assess the difficulty index of each item of an Economics Achievement test with the Rasch model. The infit and outfit as well as the reliability of the test were determined. Three research questions were drawn to guide the study. A sample of 200 was randomly selected using simple random sampling of balloting and proportionate stratified random sampling. The instrument of the study was an Economics Achievement Test with 100 items. The test has face and content validities. It has a reliability coefficient of 0.86 established through the use of Kuder-Richardson 20 method. A Rasch model software of Winsteps version 3.75 was used to analyse the data collected. The result identified the difficulty index of each item. The infit and outfit of both MNSQ and ZSTD were determined. The reliability of the Economics Achievement Test was estimated. It was recommended among others that Rasch model should always be used in assessing the item difficulty of a test and ensure the stability of item parameters.
本研究旨在运用拉施模型评估一份经济学成绩测试中各项目的难度指数。确定了测试的内拟合和外拟合以及可靠性。提出了三个研究问题以指导该研究。采用抽签简单随机抽样和按比例分层随机抽样的方法，随机抽取了200个样本。本研究的工具是一份包含100个项目的经济学成绩测试。该测试具有表面效度和内容效度。通过使用库德-理查森20方法确定其信度系数为0.86。使用Winsteps 3.75版本的拉施模型软件对收集到的数据进行分析。结果确定了每个项目的难度指数。确定了MNSQ和ZSTD的内拟合和外拟合。估计了经济学成绩测试的可靠性。其中建议，在评估测试项目难度时应始终使用拉施模型，并确保项目参数的稳定性。
