Statistical considerations for assessing precision of heterogeneous duplicate measurements: An application to pharmaceutical bioanalysis

Duplicate analysis is a strategy commonly used to assess precision of bioanalytical methods. In some cases, duplicate analysis may rely on pooling data generated across organizations. Despite being generated under comparable conditions, organizations may produce duplicate measurements with different precision. Thus, these pooled data consist of a heterogeneous collection of duplicate measurements. Precision estimates are often expressed as relative difference indexes (RDI), such as relative percentage difference (RPD). Empirical evidence indicates that the frequency distribution of RDI values from heterogeneous data exhibits sharper peaks and heavier tails than normal distributions. Therefore, traditional normal-based models may yield faulty or unreliable estimates of precision from heterogeneous duplicate data. In this paper, we survey application of the mixture models that satisfactorily represent the distribution of RDI values from heterogeneous duplicate data. A simulation study was conducted to compare the performance of the different models in providing reliable estimates and inferences of percentile calculated from RDI values. These models are readily accessible to practitioners for study implementation through the use of modern statistical software. The utility of mixture models are explained in detail using a numerical example.     

Parametric and nonparametric methods for confidence intervals and sample size planning for win probability in parallel-group randomized trials with Likert item and Likert scale data

Data on the Likert scale are ubiquitous in medical research, including randomized trials. Statistical analysis of such data may be conducted using the means of raw scores or the rank information of the scores. In the context of parallel-group randomized trials, we quantify treatment effects by the probability that a subject in the treatment group has a better score than (or a win over) a subject in the control group. Asymptotic parametric and nonparametric confidence intervals for this win probability and associated sample size formulas are derived for studies with only follow-up scores, and those with both baseline and follow-up measurements. We assessed the performance of both the parametric and nonparametric approaches using simulation studies based on real studies with Likert item and Likert scale data. The simulation results demonstrate that even without baseline adjustment, the parametric methods did not perform well, in terms of bias, interval coverage percentage, balance of tail error, and assurance of achieving a pre-specified precision. In contrast, the nonparametric approach performed very well for both the unadjusted and adjusted win probability. We illustrate the methods with two examples: one using Likert item data and the other using Like scale data. We conclude that non-parametric methods are preferable for two-group randomization trials with Likert data. Illustrative SAS code for the nonparametric approach using existing procedures is provided.     

英汉语言:不同文化背景下的思维差异

英汉两种语言的差异对人们思维方式的影响是十分明显的,具体表现为:文化背景的差异对语言表达方式的影响,语言结构的差异对思维能力的影响,文化意识的差异对跨文化交际能力的影响。     

浅析区域经济发展的差距

改革开放以来,中国经济的发展极为迅速,东西部区域发展差距也迅速拉大,并呈加速扩大的趋势。究其原因,主要是市场经济发育程度的差异很大。因此,进一步完善市场经济制度,通过区域发展战略的调整以及国家政策的倾斜,来加快落后地区的发展,以期缩小区域发展的差距。     

21世纪东亚价值观--从比较思想的角度

任何思想和文化的本质都不是独自形成的,而是与其他思想和文化有着密切的关联.所以通过比较韩国、中国、日本的思想和文化的本质,找出东亚三国思想的差异性,通过与西欧中心主义的比较找出其普遍性,从而使相对独立发展的,不强求相互同一化,但相互促进的东亚文化,成为21世纪东西方思想文化的共同价值.     

跨文化翻译中的文化差异及其处理方法与技巧

不同国家和民族的语言中包含着许多文化差异信息,因此,翻译既是语言的翻译,也是文化的翻译。跨文化翻译过程中处理文化差异的方法主要有直译、套译、意译等。     

建设医学院校研究生英语自主学习中心的设想

研究生英语教学中普遍存在着英语学习者个体差异大的矛盾。多媒体计算机辅助语言学习(MCALL)以其在自主学习和个性化学习方面的优势,为学习者提供巨大的便利和发展空间。它很好地缩小了学习者个体差异,尤其对医学英语和商务英语等特殊用途英语的学习,所起作用十分明显。文章介绍了多媒体计算机辅助语言教学理论的发展,阐述了建立多媒体英语自主学习中心的必要性,提出了设置自主学习中心的具体实施方案。     

“江湖”:中国文化的另一个视窗——兼论“差序格局”的社会结构内涵

江湖是熟人社会以外混沌、非透明、乏规则的互动空间。在这种互动空间里,形成了历时性的江湖传统。它在组织模式上体现为模拟血缘关系的异姓结拜和结盟拜会,在价值模式上体现为等差有序、内外有别的义气。江湖传统表面上看主要存在于下层群体当中,实际上深嵌于常态文化体系之内。江湖作为一个独特的视窗,在中西学者熟悉的儒教中国、帝制中国、乡土中国等局部意象之外,提供了一个关于传统中国的整合性框架,即江湖中国。由此,传统中国社会结构的立体特征能够得到完整呈现。基层的乡土社区层面,呈现为费孝通所说的差序格局特征,顶端的庙堂层面同样如此。而介于乡土社区与庙堂之间的混沌江湖,仍旧要援引熟人世界的结构模型,同样讲究差序之别。这种一般社会层面的事实证据表明,差序格局概念确实具有立体社会结构内涵。     

农产品电商对小农户有机衔接现代农业发展效率的影响研究

随着“互联网+”现代农业的普及,小农户通过参与农产品电商活动提升与现代农业发展有机衔接效率的机制逐渐形成。基于2014-2019年江苏、河北和山东等3个省份176个行政村2 744户林果种植小农户跟踪调查,采用基于熵值的层次分析法构建小农户和现代农业发展有机衔接三级效率指标体系,从发展能力、组织化程度、增收空间和社会化服务体系等4个方面设置13个微观指标,建立双重差分倾向得分匹配模型考察农产品电商行为对小农户有机衔接现代农业发展效率的处理效应。实证结果表明,小农户和现代农业发展有机衔接的综合效率及发展能力、组织化程度、增收空间和社会化服务体系等细分效率均逐年提升且增速放缓;农产品电商对小农户有机衔接现代农业发展的综合效率具有积极提升作用,对组织化程度和社会化服务体系的影响较为显著,对发展能力和增收空间的影响亟待更长周期的观察。