经济管理类专业统计学课程教学改革研究

统计学是一门实践性和应用性很强的学科,是一门方法论科学,是高校经济管理类专业必修的专业基础课程。在新形势下,其教学面临着诸多挑战,因此对统计学教学进行改革极为迫切。本文分别从教师和学生角度,依据学生学习情况、教学内容、教学方法、教学手段、考核方式等方面对经济管理类专业统计学课程教学改革提出了思路和建议。     

Subspace design of low-rank estimators for higher-order statistics

Higher-order statistics (HOS) are well known for their robustness to additive Gaussian noise and ability to preserve phase. HOS estimates, on the other hand, have been criticized for high complexity and the need for long data in order to maintain small variance. Since rank reduction offers a general principle for reduction of estimator variance and complexity, we consider the problem of designing low-rank estimators for HOS. We propose three methods for choosing the transformation matrix that reduces the mean-square error (MSE) associated with the low-rank HOS estimates. We also demonstrate the advantages of using low-rank third-order moment estimates for blind system estimation. Results indicate that the full rank MSE corresponding to some data length N can be attained by a low-rank estimator corresponding to a length significantly smaller than N.     

On the misinterpretation of histograms and box plots

Recent studies have shown that the interpretation of graphs is not always easy for students. In order to reason properly about distributions of data, however, one needs to be able to interpret graphical representations of these distributions correctly. In this study, we used Tversky’s principles for the design of graphs to explain how 125 first-year university students interpreted histograms and box plots. We systematically varied the representation that accompanied the tasks between students to identify how the design principles affected students’ reasoning. Many students displayed misinterpretations of histograms and box plots, despite the fact that they had the required knowledge and time to interpret the representations correctly. We argue that the combination of dual process theories and Tversky’s design principles provides a promising theoretical framework, which leads to various possibilities for future research.     

Evaluation of a New Mean Scaled and Moment Adjusted Test Statistic for SEM

Recently a new mean scaled and skewness adjusted test statistic was developed for evaluating structural equation models in small samples and with potentially nonnormal data, but this statistic has received only limited evaluation. The performance of this statistic is compared to normal theory maximum likelihood and 2 well-known robust test statistics. A modification to the Satorra–Bentler scaled statistic is developed for the condition that sample size is smaller than degrees of freedom. The behavior of the 4 test statistics is evaluated with a Monte Carlo confirmatory factor analysis study that varies 7 sample sizes and 3 distributional conditions obtained using Headrick's fifth-order transformation to nonnormality. The new statistic performs badly in most conditions except under the normal distribution. The goodness-of-fit χ² test based on maximum-likelihood estimation performed well under normal distributions as well as under a condition of asymptotic robustness. The Satorra–Bentler scaled test statistic performed best overall, whereas the mean scaled and variance adjusted test statistic outperformed the others at small and moderate sample sizes under certain distributional conditions.     

概率加法公式的简单推导

基于两个事件的概率加法公式,推导出了3⁵个事件的概率加法计算公式。通过总结多个事件概率加法公式的一般规律,得到n个事件的概率加法公式。     

The information seeking behaviour of the users of digital scholarly journals

The article employs deep log analysis (DLA) techniques, a more sophisticated form of transaction log analysis, to demonstrate what usage data can disclose about information seeking behaviour of virtual scholars – academics, and researchers. DLA works with the raw server log data, not the processed, pre-defined and selective data provided by journal publishers. It can generate types of analysis that are not generally available via proprietary web logging software because the software filters out relevant data and makes unhelpful assumptions about the meaning of the data. DLA also enables usage data to be associated with search/navigational and/or user demographic data, hence the name ‘deep’. In this connection the usage of two digital journal libraries, those of EmeraldInsight, and Blackwell Synergy are investigated. The information seeking behaviour of nearly three million users is analyzed in respect to the extent to which they penetrate the site, the number of visits made, as well as the type of items and content they view. The users are broken down by occupation, place of work, type of subscriber (“Big Deal”, non-subscriber, etc.), geographical location, type of university (old and new), referrer link used, and number of items viewed in a session.     

基于引文与载文指标的中国科普领域核心期刊分析

【目的】探索中国科普领域核心期刊,帮助了解科普事业发展的理论支撑和科普文章发表的主要阵地,进而有针对性地采取措施,推动中国科普期刊的建设和发展。【方法】 主要采用引文分析方法和载文统计方法。基于引文分析的科普主题文献来源于CSSCI数据库;基于载文统计的科普主题文献来源于CNKI数据库。【结果】 基于CSSCI引文分析的科普主题文献被引频次最高的10本中文期刊,将其称为中国科普领域高被引核心期刊;基于CNKI数据的科普主题文献载文量最高的10本中文期刊,除了已经进入中国科普领域高被引核心期刊阵营的两本之外,将其余8本期刊称为中国科普领域高载文核心期刊。【结论】 中国科普领域高被引核心期刊,为中国科普事业的发展发挥着提供理论支撑的作用,应更多地吸收全球科普发展的理论和实践经验;中国科普领域高载文核心期刊,是中国科普文章发表的主要阵地,今后应该更加注重提高科普文章的质量。     

中美高职高专图书馆的比较分析

将中美两国高职高专院校图书馆学生人均藏书量、人均年增图书量、其他文献收藏、复本量和图书馆经费等予以比较,可发现在大多方面,美国做得比中国更科学,值得学习、参考。通过对比,感到我国高职高专图书馆应降低藏书量标准,更关注提高藏书质量;要改进对馆员的管理,提高办馆水平;应抛弃重藏轻用思想,改善评估方法;要引入监督机制,促进其发展。参考文献11。     

Dynamic Monte Carlo simulation of linear SAW polymer chain near a flat surface

Investigation of the conformational properties of a SAW polymer chain near an impenetrable, non-interacting flat surface showed that the chain at first contracted and orientated itself to slightly parallel when it pulled close to the surface and at last elongated and reoriented itself to slightly perpendicular to the surface at very small distance from the surface. Simulation showed that most of the disappeared configurations were of large size at moderate distance from the surface while they were of small size at very small distance from the surface; and that the mean-square end-to-end distance was much more prone to be influenced by the surface than the mean-square radius of gyration . The orientational correlation between the direction of the longest principal axis of the moment of inertia and end-to-end vector was also discussed.