Measurable Outcomes of Two Methods of Teaching Experimental Geometry

Analytic and nonanalytic dimensions of cognitive styles and discovery and expository teaching strategies were combined to form a 2 x 2 design. Five tests were used. Subjects were selected according to their cognitive styles in each of the two experimental schools. After seven weeks of mathematics instruction, two periods of one-hour duration per week, the students’ posttest scores were analyzed to determine the effects of the two cognitive styles as well as the two teaching methods on retention and transfer of mathematics tasks. The ANCOVA showed significant F ratios for the main effect of cognitive style. Analytic boys in the expository group scored significantly higher than nonanalytic students. The analyses revealed no significant main effect of teaching methods. In no instance was a significant difference found for girls in respect to cognitive styles or teaching methods.     

磷铁国家标准样品的研制

研制了一个磷铁国家标准样品,研制过程包括选料、加工、均检及定值均严格按照GB／T15000《标准样品工作导则》和YB／T082《冶金产品分析用标准样品技术规范》的要求进行。该标准样品经化学成分的粒度检验、均匀性检验及近一年的稳定性监测,显示均匀性和稳定性良好;定值了碳、硫、磷、硅、锰、镍、铬和钛等九个特性量值,由九个实验室采用不同原理、准确可靠的分析方法进行定值分析,保证每个元素都采用两种或两种以上的定值分析方法,确定的标准值准确、可靠,并对定值参数进行了不确定度的评估。     

Correcting for sample problems in PISA and the improvement in Portuguese students’ performance

The results of large-scale international assessments such as Programme for International Student Assessment (PISA) have attracted a considerable attention worldwide and are often used by policy-makers to support educational policies. To ensure that the published results represent the actual population, these surveys go through a thorough scrutiny to ensure their validity. One important issue that may affect the results is the occurrence of different participation rates across groups with heterogeneous average student scores. In this study, we illustrate how problems of representativeness of the samples may be corrected by the use of post-stratified weights. We use the case of Portugal, a country where we uncover a meaningful difference between the actual population and the PISA samples in terms of the distribution of students per grade and track of studies. We show that after post-stratification, the temporal evolution of the PISA scores is quite different from the one reported.     

相关G-M模型及其在不完全样本中的应用

研究了相关情况下第i个顺序统计量及其标准化变量的期望、方差、协方差以及在各阶矩上的变换作用，将Gauss—Markov定理推广至一般相关的不完全样本的情形，并用最小二乘法对顺序统计量的参数作出了最佳线性无偏估计，推导出在样本值之间不相关或相关条件下计算估计量方差的公式。     

New Confidence Intervals and Bias Comparisons Show That Maximum Likelihood Can Beat Multiple Imputation in Small Samples

When analyzing incomplete data, is it better to use multiple imputation (MI) or full information maximum likelihood (ML)? In large samples ML is clearly better, but in small samples ML’s usefulness has been limited because ML commonly uses normal test statistics and confidence intervals that require large samples. We propose small-sample t-based ML confidence intervals that have good coverage and are shorter than t-based confidence intervals under MI. We also show that ML point estimates are less biased and more efficient than MI point estimates in small samples of bivariate normal data. With our new confidence intervals, ML should be preferred over MI, even in small samples, whenever both options are available.     

The Use of Incorrect Informative Priors in the Estimation of MIMIC Model Parameters with Small Sample Sizes

Recently, advancements in Bayesian structural equation modeling (SEM), particularly software developments, have allowed researchers to more easily employ it in data analysis. With the potential for greater use, come opportunities to apply Bayesian SEM in a wider array of situations, including for small sample size problems. Effective use of Bayseian estimation hinges on selection of appropriate prior distributions for model parameters. Researchers have suggested that informative priors may be useful with small samples, presuming that the mean of the prior is accurate with respect to the population mean. The purpose of this simulation study was to examine model parameter estimation for the Multiple Indicator Multiple Cause model when an informative prior distribution had an incorrect mean. Results demonstrated that the use of incorrect informative priors with somewhat larger variance than is typical, yields more accurate parameter estimates than do naïve priors, or maximum likelihood estimation. Implications for practice are discussed.     

Self-assessment of writing in independent language learning programs: The value of annotated samples

The availability of multi-media technologies in education has made the option of independent learning increasingly attractive. Whilst independent learning presents learners with a more flexible learning context, it also presents new challenges in assessment in that the onus is placed upon the learners themselves to monitor and evaluate their own learning.This paper reports on the development of an approach to learner self-assessment which aims to facilitate the self-assessment of performance on extended-response writing tasks. Whilst such tasks are typical within current approaches to communicative language learning, a review of the self-assessment literature reveals no precedent for how actual task performance might be effectively and reliably self-assessed. A methodology was therefore developed which used annotated samples of learner-produced texts, where the annotations would elucidate both the criteria by which performance should be judged and the standards expected, thus enabling learners to assess their own performances by comparing their work with these samples. The methodology was trialled on a small sample of students. It was found to be both reliable and useful, allowing students not only to accurately evaluate their own performance but also to learn new language skills from the samples.     

对分析化学实验的几点改进及废弃物的回收利用

对分析化学实验进行了几点改进,并对实验中一些废弃物的回收利用进行了研究.     

指甲附着物DNA检测在凶杀案中的应用

报道了指甲附着物DNA的检验在刑事案件中的成功应用，并讲述了检验过程中的二组分混合DNA分析的一些问题和解决方法。     

案例教学在职教中的运用

案例教学被公认为是一种较好的MBA教学方法,它能培养学生解决实际问题的能力.职业学校应转变教育观念,改革教学方法,在日常教学中引用案例教学.