THE SUBSET SELECTION TECHNIQUE FOR MULTIPLE-CHOICE TESTS: AN EMPIRICAL INQUIRY

The impact of the Subset Selection Technique (SST) for administering and scoring multiple-choice items on certain properties of a test was compared with that of the two other commonly used methods, the Number Right (NR) and the Correction for Guessing Formula (CFG). Under SST, examinees are instructed to select any number of response alternatives, the objective being to include the correct answer in the chosen set. The effects of each scoring method on the psychometric properties of a test and on the performance of examinees with different achievement levels and/or risk-taking propensities were investigated. Results indicated that SST outperformed the other two methods, producing not only higher reliability and validity coefficients for the test, but doing so without favoring high risk takers. The superiority of SST may be attributed to two interrelated factors: the efficiency of the technique in controlling for guessing and the encouragement provided examinees to use their partial knowledge in responding.     

A MONTE CARLO STUDY OF ITEM SAMPLING (VERSUS TRADITIONAL SAMPLING) FOR NORM CONSTRUCTION1

Using a computer-based model of an item trace line, a random sampling experiment concerned with comparing item sample estimates to traditional (examinee) sample estimates of the mean and variance of a distribution of test scores was conducted. The results indicated that the optimal method for estimating a test's parameters may depend on several conditions. As expected, item sampling proved superior to traditional sampling in estimating test means under all conditions. However, with certain test lengths, ranges of item difficulty, and discrimination, traditional sampling provided better estimates of test variance than did item sampling.     

光学系统成像的仿真研究

利用波动光学的基本理论,对复杂的光学系统的成像进行分析,并结合MATLAB语言的编程和图像处理功能。通过数值模拟形象地把光学系统成像的结果显示出来。结果表明,在对单透镜系统成像分析的基础上,可以对各种复杂的光学系统的成像进行分析。利用这种方法作为辅助教学手段,有助于学生更加深刻地理解光学系统的成像,提高教学质量。     

OPERATIONALIZING IDENTITY IN ACTION: A COMPARATIVE STUDY OF DIRECT VERSUS PROBABILISTIC MEASURES OF CURRICULAR ROLE IDENTITY FOR INQUIRY-BASED SCIENCE TEACHING

Teachers’ curricular role identities are those dimensions of their professional identities concerned with the use of curriculum materials. In a previous study, we developed and tested a survey instrument designed to measure preservice elementary teachers’ development of curricular role identity for science teaching through their use of science curriculum materials. In this follow-up study, a revised version of the survey was administered to a second group of preservice elementary teachers in the same science methods course, and data were analyzed within and across years. Results from this study suggest that preservice teachers articulated important similarities and differences between the curricular role identities for science teaching they attributed to themselves and to more experienced elementary teachers. Over time, they were often able to begin to appropriate the curricular role identities for science teaching that they attributed to more experienced elementary teachers. However, findings from the second survey administration also suggest that preservice teachers’ curricular role identities for science teaching are more stable when characterized by their actual curriculum design practices than when characterized by comparative, probabilistic means. These findings have important implications for science teacher education and curriculum development, as well as the operationalization of curricular role identity in education research.     

CREATIVITY: IDIOGRAPHIC VERSUS NOMOTHETIC APPROACH

Two main approaches exist in the study of personality: idiographic vs. nomothetic. A combination of both is called psychological biography, i.e., an integration of nomothetic objectives and idiographic completeness. This approach was applied by Gardner in analyzing seven creative‐productive personalities. In Gardner's view the development of creating minds is not only dependent on a supportive environment, but also cultural and/or societal acceptance. The mastery of a particular creative direction starts in the early years and mastery needs exercise. Moreover, the examples given by Gardner lead to the conclusion that creativity does not exist as a general trait, but is alway domain specific.     

武清地热热储数值模拟

采用 AU TOU GH2热储计算软件对天津市武清县地热热储进行数值模拟计算 ,分析热储在不同开发利用条件下的特征 .主要针对无回灌和有回灌两种生产情况 ,分析地热热储的温度、压力随时间和距离的变化 ,还分析随地热水的生产 ,地热热储的生产能力、水位和压力的变化以及回灌对生产井的冷却效应     

ITEM DIFFICULTY LEVEL AND SEQUENCE EFFECTS IN MULTIPLE-CHOICE ACHIEVEMENT TESTS

Certain testing authorities have implied that the proportion of examinees who answer an item correctly may be influenced by the difficulty of the immediately preceding item. If present, such a "sequence effect" would cause p (as an estimate of item difficulty level) to misrepresent an item's "true" level of difficulty. To investigate this hypothesis, a balanced Latin square design was used to rearrange examination items into various test forms. A unique analysis of variance procedure was used to analyze the resulting data. The alleged sequence effect was not found. Certain limitations preclude the generalization of this finding to all students or to all testing situations. However, the evidence provided by this investigation does suggest that comments relating to sequence effects should be qualified as compared with presently appearing statements.     

MULTIPLE CHOICE VERSUS TRUE-FALSE: A COMPARISON OF RELIABILITIES AND CONCURRENT VALIDITIES

The purpose of this study was to compare the reliabilities of true-false (TF) and multiple choice (MC) tests and to determine the concurrent validities of both. Two methods, judgmental and discrimination, were devised for objectively converting MC items to TF form. The TF items generated by the two methods from 70-item MC natural science and social studies tests were incorporated in eight final forms which were differentiated by subject matter, conversion method, and item form order. A sample of 1018 nonurban high school students each responded to one of the eight forms. Examinees tried three TF items for every pair of MC items attempted. The TF tests were significantly less reliable than the MC tests but did tend to measure the same thing as the corresponding MC tests.     

POSITIONAL RESPONSE SET AMONG HIGH SCHOOL STUDENTS ON MULTIPLE-CHOICE TESTS

Investigations of positional response set in examinees of multiple-choice items have shown conflicting results. This study attempted to clarify this controversy. Over 1000 subjects were assigned at random to one of nine forms of a specially prepared vocabulary test. The difference among forms related to the position of the correct answers and the most popular distractor as determined by prior administrations of the test. The forms of the test were constructed so that if a universal positional response set existed, it would manifest itself as a difference of means of scores obtained on selected items dispersed throughout each of the different forms. The results of the analysis of variance showed no significant evidence of interindividual positional response set.     

搅拌釜内空气-PPG分散特性的数值模拟与实验测量

文章借助FLUENT软件,采用Euler-Euler方法、Laminar层流模型、MFR法处理旋转搅拌桨、气泡单一尺寸假设,对搅拌釜内空气-PPG体系的气含率和搅拌功率进行了数值模拟,模拟结果与实验值吻合较好.同时,考察了搅拌转速和通气流量对气含率和通气搅拌功率的影响.结果表明,数值模拟所选取的模型,能较好地模拟搅拌釜内空气-PPG体系的分散特性.     

A COMPARISON OF THE RELIABILITY AND VALIDITY OF TWO METHODS FOR ASSESSING PARTIAL KNOWLEDGE ON A MULTIPLE-CHOICE TEST

Differential weighting of response alternatives and confidence testing have been proposed as ways to assess partial knowledge on multiple-choice tests. 211 students in an educational measurement course took their midterm examination under one of three procedures. Results from those students administered the test under conventional directions provided a baseline for comparing, in terms of reliability and validity, the results from students who took the test under the differential weighting of response alternatives or the confidence testing instructions. Reliability was estimated by the split-half technique. Validity was estimated by correlating midterm test scores with scores on a final examination. This investigation provides some support for the contention that validity can be improved using more sophisticated testing techniques. Suggestions for the conduct of more definitive studies were offered.