Inferences on the Means of Two Log-Normal Distributions: A Computational Approach Test

In this article, we propose a novel approach for testing the equality of two log-normal populations using a computational approach test (CAT) that does not require explicit knowledge of the sampling distribution of the test statistic. Simulation studies demonstrate that the proposed approach can perform hypothesis testing with satisfying actual size even at small sample sizes. Overall, it is superior to other existing methods. Also, a CAT is proposed for testing about reliability of two log-normal populations when the means are the same. Simulations show that the actual size of this new approach is close to nominal level and better than the score test. At the end, the proposed methods are illustrated using two examples.     

Statistical testing strategies for assessing treatment efficacy and marker accuracy in phase III trials

When a candidate predictive marker is available, but evidence on its predictive ability is not sufficiently reliable, all‐comers trials with marker stratification are frequently conducted. We propose a framework for planning and evaluating prospective testing strategies in confirmatory, phase III marker‐stratified clinical trials based on a natural assumption on heterogeneity of treatment effects across marker‐defined subpopulations, where weak rather than strong control is permitted for multiple population tests. For phase III marker‐stratified trials, it is expected that treatment efficacy is established in a particular patient population, possibly in a marker‐defined subpopulation, and that the marker accuracy is assessed when the marker is used to restrict the indication or labelling of the treatment to a marker‐based subpopulation, ie, assessment of the clinical validity of the marker. In this paper, we develop statistical testing strategies based on criteria that are explicitly designated to the marker assessment, including those examining treatment effects in marker‐negative patients. As existing and developed statistical testing strategies can assert treatment efficacy for either the overall patient population or the marker‐positive subpopulation, we also develop criteria for evaluating the operating characteristics of the statistical testing strategies based on the probabilities of asserting treatment efficacy across marker subpopulations. Numerical evaluations to compare the statistical testing strategies based on the developed criteria are provided.     

Blinded continuous monitoring in clinical trials with recurrent event endpoints

In studies with recurrent event endpoints, misspecified assumptions of event rates or dispersion can lead to underpowered trials or overexposure of patients. Specification of overdispersion is often a particular problem as it is usually not reported in clinical trial publications. Changing event rates over the years have been described for some diseases, adding to the uncertainty in planning. To mitigate the risks of inadequate sample sizes, internal pilot study designs have been proposed with a preference for blinded sample size reestimation procedures, as they generally do not affect the type I error rate and maintain trial integrity. Blinded sample size reestimation procedures are available for trials with recurrent events as endpoints. However, the variance in the reestimated sample size can be considerable in particular with early sample size reviews. Motivated by a randomized controlled trial in paediatric multiple sclerosis, a rare neurological condition in children, we apply the concept of blinded continuous monitoring of information, which is known to reduce the variance in the resulting sample size. Assuming negative binomial distributions for the counts of recurrent relapses, we derive information criteria and propose blinded continuous monitoring procedures. The operating characteristics of these are assessed in Monte Carlo trial simulations demonstrating favourable properties with regard to type I error rate, power, and stopping time, ie, sample size.     

Modifications of sequential designs in bioequivalence trials

Bioequivalence (BE) studies are designed to show that two formulations of one drug are equivalent and they play an important role in drug development. When in a design stage, it is possible that there is a high degree of uncertainty on variability of the formulations and the actual performance of the test versus reference formulation. Therefore, an interim look may be desirable to stop the study if there is no chance of claiming BE at the end (futility), or claim BE if evidence is sufficient (efficacy), or adjust the sample size. Sequential design approaches specially for BE studies have been proposed previously in publications. We applied modification to the existing methods focusing on simplified multiplicity adjustment and futility stopping. We name our method modified sequential design for BE studies (MSDBE). Simulation results demonstrate comparable performance between MSDBE and the original published methods while MSDBE offers more transparency and better applicability. The R package MSDBE is available at https://sites.google.com/site/modsdbe/ . Copyright © 2015 John Wiley & Sons, Ltd.     

解读人与自然的和谐

人与自然和谐包含着丰富和深刻的内涵 ,从理论层面上看 ,它应是人与自然互相适应的辩证统一 ;从实践层面上讲 ,它应是人与自然双方均处于既被改造又应保护的关系之中。必须反对在这个问题上的各种片面的观点与看法     

国有企业战略性调整问题研究

从市场经济演进的历史和计划经济实践的历程两个角度 ,考察了国有企业的性质 ,设计了我国国有企业产业定位的战略方案 ,分析了我国国有企业战略性调整的障碍 ,提出了国有企业进行战略性调整的途径     

基于就业态势分析的交通运输专业人才培养思路调整方案

高校本科专业的就业发展态势反映了社会需求的变化趋势。高校专业教育的人才培养目标必须也只能与社会需求进行模糊的、大范围的对接。交通运输专业要实现这种对接,应当以综合交通运输理念为指导,强化在运输组织管理领域的传统优势,拓展运输经济、技术管理等专业内涵,按综合交通运输体系的要求修订人才培养目标,制定开放式的专业培养计划和网络化的课程体系,在实验、实习、毕业设计等环节强调职业化训练。     

中古均田制度的农史观察

均田制是中国古代重要的土地制度之一,它的兴起与发展,与中古时代社会变迁与农业发展的宏观背景相联系:均田制与魏晋南北朝时期的民族大迁移、大融合相关联,既是中原既有生产关系与少数民族新型社会形态相结合的产物,也与民族迁徙而引发的农牧结构大调整和农牧技术的大发展密切相关。从这一视角出发亦可见均田制实施与隋唐盛世之联系。     

"民官比"不是影响政治体制改革的重要因素

在政治体制改革中,公务员或国家干部人数的多少并不是一个关键因素,重要的是必须把政府的社会定位(包括角色、权力和责任)划分清楚。与世界各国相比较,我国197.69∶1(或116.27∶1)的“民官比”并不高,因此,今后的政治体制改革不需要再把精力集中在“精简”上,而应按邓小平的部署,首先把党政分开和权力下放的工作做好。毕竟“小政府”是指“政府权力受限制”,而非“人数更少”;“大社会”是指“社会权利更广泛”,而非“人数更多”。     

为国家教育妇女：加纳的教育改革与性别问题

1986改革中,加纳政府根据结构调整方案(SAP)和2020计划,关注教育中存在性别的不平等现象,努力解决女生在科学、数学和技术课程(SMT)的学业成绩、入学率等问题,并建立女子教育联合会.问题的解决要依靠真正普及免费的义务教育以及将妇女教育延伸到职业和高等教育机构.