Wilcoxon–Mann–Whitney test for stratified samples and Efron's paradox dice

Two-treatment multi-center clinical trials are the most common type of clinical trials in practice. The aim of this paper is to discuss a curious property of certain standard nonparametric procedures used in the analysis of such clinical trials. Different analyses of a simulated data example are presented, which lead to contrasting and surprising results. The source of the potentially misleading outcome is then explored while relating the simulated data with the concept of Efron's paradox dice and the notion of nontransitivity. With the root of the problem established, an alternate nonparametric method from the literature is shown to address the problem. Finally, pointing out an interpretational concern of using the alternate procedure, a modification to this procedure is also suggested and corresponding theoretical results are presented.     

震荡与冲突：近代中国社会结构转型探析

中国传统社会结构乃是权威—依附模式。鸦片战争以后 ,随着家族中心主义的动摇、阶级的裂变和改组、社会群体的嬗变与激增以及沿海与内地、城市与乡村二元格局的出现 ,近代中国社会结构呈现出从宗法社会到二元结构社会转型的态势。     

Estimating household structure in ancient China by using historical data: a latent class analysis of partially missing patterns

Summary.  Social data often contain missing information. The problem is inevitably severe when analysing historical data. Conventionally, researchers analyse complete records only. Listwise deletion not only reduces the effective sample size but also may result in biased estimation, depending on the missingness mechanism. We analyse household types by using population registers from ancient China (618–907 AD) by comparing a simple classification, a latent class model of the complete data and a latent class model of the complete and partially missing data assuming four types of ignorable and non-ignorable missingness mechanisms. The findings show that either a frequency classification or a latent class analysis using the complete records only yielded biased estimates and incorrect conclusions in the presence of partially missing data of a non-ignorable mechanism. Although simply assuming ignorable or non-ignorable missing data produced consistently similarly higher estimates of the proportion of complex households, a specification of the relationship between the latent variable and the degree of missingness by a row effect uniform association model helped to capture the missingness mechanism better and improved the model fit.     

湖北省高校科技成果转化的现状调查与分析

通过对高校科技工作管理者、高校教师以及部分企业的调研发现,目前影响湖北省高校科技成果转化的因素主要是政府管理、资金投入、高校观念转变与机制创新、企业重视等方面,并提出相应的对策与建议.     

Bayesian networks for imputation

Summary.  Bayesian networks are particularly useful for dealing with high dimensional statistical problems. They allow a reduction in the complexity of the phenomenon under study by representing joint relationships between a set of variables through conditional relationships between subsets of these variables. Following Thibaudeau and Winkler we use Bayesian networks for imputing missing values. This method is introduced to deal with the problem of the consistency of imputed values: preservation of statistical relationships between variables ( statistical consistency ) and preservation of logical constraints in data ( logical consistency ). We perform some experiments on a subset of anonymous individual records from the 1991 UK population census.     

试论企业核心能力与企业经营战略

企业核心能力要准确理解 ,应区分“资源”与“能力”、“基本能力”与“核心能力”以及基于动态的一些观点 ,由此 ,对企业核心能力进行了界定。企业核心能力的逻辑结构应考虑到企业 /行业的技术经济特征、生命周期 ,不能理解为几项关键技能的简单组合。最后指出中国企业培育核心能力的战略选择。     

Tl_2Ba_2CaCu_2O_8超导体的能带结构及其与晶体中氧缺位的关系

本文利用EHT(Extended Huckel Method)紧束缚能带计算方法,计算了Tl_2Ba_2CaCu_2O_8在晶体中三种不同氧缺位条件下的电子能带,讨论了晶体中不同氧缺位对该超导体的能带结构,体系总能量,总态密度和Cu—O面上Cu和O的电荷分布的影响,指出这三种氧缺位结构都有可能存在于该超导体中,并且对超导电性的贡献是相同的。     

城市绿地系统的结构规划

城市绿地系统结构是系统规划建设的基础框架,对城市绿地形成完整有机的系统具有重要作用。本文以城市绿地系统结构为研究对象,在分析其内涵特征和系统化发展趋势的基础上,力图探讨较为系统的现代城市绿地系统结构规划方法。     

西部少数民族地区经济发展的资金瓶颈及资本形成的途径

西部少数民族地区的经济发展是中国经济发展战略的重要组成部分,西部大开发为少数民族地区经济发展提供了契机。发展经济学的资本形成理论认为,资金是欠发达地区经济发展的瓶颈。西部少数民族地区经济发展正面临着这个难题,因此,制定出行之有效的资本形成对策是发展少数民族地区经济的途径。     

武汉制造业人力资本利用效率低下的原因

人力资本对经济增长或发展的实际作用，不仅取决于其存量的高低，还取决于其实际利用效率的大小。而人力资源利用效率低下是我国当前人力资本发展的突出矛盾和问题。以武汉制造业为对象，分析了导致其人力资本利用效率低下的两大关键因素：产权制度缺陷和人力资本投资与配置不当。