Estimation of variance in bivariate normal distribution after the preliminary test of homogeneity

A preliminary test estimator of variance in the bivariate normal distribution is proposed after the Pitman–Morgan test of homogeneity of two variances. The bias and mean square error of the estimator are derived. The relative efficiency (RE) of the preliminary test estimator is studied. Computations and 3D graphs of RE for different parameters are analyzed. In order to get the maximum RE, recommendations of the significance level for the preliminary test are given for various sample sizes by using the max–min criterion.     

Shrinkage estimation of proportion via logit penalty

By releasing the unbiasedness condition, we often obtain more accurate estimators due to the bias–variance trade-off. In this paper, we propose a class of shrinkage proportion estimators which show improved performance over the sample proportion. We provide the “optimal” amount of shrinkage. The advantage of the proposed estimators is given theoretically as well as explored empirically by simulation studies and real data analyses.     

Is the web a promising tool for data collection in developing countries? An analysis of the sample bias of 10 web and face-to-face surveys from Africa,Asia, and South America

Whereas the sample composition biases of web surveys have been discussed extensively for developed countries, studies for developing countries are scarce. This article helps to fill that gap by comparing similar non-probability-based web surveys (WEB) and probability-based face-to-face (F2F) surveys both to each other and to the labor force. An analysis of WageIndicator data on work and wages derived from surveys held in 2009–2013 in 10 developing countries (WEB-sample N = 9135; F2F-sample N = 14,659), shows that F2F samples resemble the labor force to a larger extent than web samples do. In both cases, individuals in their 20s and early 30s are overrepresented, and younger and older respondents are underrepresented. This trend is more pronounced in WEB than in F2F samples. However, the differences converge in countries with higher Internet usage. A comparison of the WEB and F2F samples shows that compositions differ greatly, with web respondents being younger, more often male, more often living alone, and higher educated, although these differences are smaller in countries with higher Internet usage. Given the cost differences between the two survey modes, one should nevertheless consider the potential of web surveys as an instrument to gain explorative insights, specifically when searching for individuals with particular characteristics.     

“新金融”发展态势及上海的鼓励政策研究

中国式"新金融"规模不断扩大,对中国经济发展和宏观调控产生了重要影响。它在一定程度上使得经济增长与实体经济背离,也未能完全解决中小企业融资难问题。当前政策的出发点,不应仅出于控制金融风险而对"新金融"加以限制,更多的还是应考虑如何加大力度引导资金流向中小企业等实体经济。上海"新金融"政策定位,应借助"新金融"体系,引导社会资金流向实体经济,并以金融支持科技创新和产业升级转型为重点,以活跃和繁荣金融机构和中介服务体系为抓手,构建上海"新金融"鼓励政策。     

瑞典修改《医疗生物银行法》对我国的启示

瑞典的《医疗生物银行法》在实施过程中出现适用范围有限、伦理原则缺失、有关职责界定不清等问题,科学界和医疗界提议出台新的生物银行法以替代旧法,促进医疗领域健康发展。瑞典新的生物银行法报告在尊重个体完整和隐私的前提下,将监管所有人类组织样本的收集、存储和使用,并将完善样本捐献者的知情同意,强化样本捐献者的自决权,增加可追溯性规定和样本库个人资料处理原则,申明生物样本跨界合作的安全问题,对正在修订《涉及人的生物医学研究伦理审查办法》的我国具有借鉴意义。     

Bayesian sample‐size determination methods considering both worthwhileness and unpromisingness for exploratory two‐arm randomized clinical trials with binary endpoints

A randomized exploratory clinical trial comparing an experimental treatment with a control treatment on a binary endpoint is often conducted to make a go or no‐go decision. Such an exploratory trial needs to have an adequate sample size such that it will provide convincing evidence that the experimental treatment is either worthwhile or unpromising relative to the control treatment. In this paper, we propose three new sample‐size determination methods for an exploratory trial, which utilize the posterior probabilities calculated from predefined efficacy and inefficacy criteria leading to a declaration of the worthwhileness or unpromisingness of the experimental treatment. Simulation studies, including numerical investigation, showed that all three methods could declare the experimental treatment as worthwhile or unpromising with a high probability when the true response probability of the experimental treatment group is higher or lower, respectively, than that of the control treatment group.     

The moderating effects of home region orientation on R&D investment and international SME performance: Lessons from Korea

Drawing from the resource-based view, we investigate how firm and country combinations affect international SME performance. Using a sample of 2676 international Korean SMEs, we explore the relationships among SME R&D investment, home region orientation and financial performance. Results show that R&D investment has a horizontally inverted S-shaped relationship with performance reflecting cost leadership, stuck in the middle, and differentiation strategies. We also find that a home region orientation moderates the relationship between R&D investment and performance. Home region orientation positively moderates the relationship when R&D investment reflects cost leadership or differentiation but negatively moderates a stuck in the middle strategy.     

组织派系中的“小世界”对知识扩散的影响研究评述

企业及学校中的"团队"建设和"团队"教学无不体现着小世界模型对于组织派系内创新知识的传播和培训效果的迁移的指导作用.本文介绍了小世界社会网络模型的基本特征和理论来源,以及它在实际工作和教学学习中的运用,并在最后提出了该模型进一步发展的趋势.     

我国上市公司独立审计质量的博弈模型刻画及其分析

本文分析了我国上市公司独立审计中会计师事务所、公司管理当局、独立董事、监管部门在审计行为中的博弈关系,应用博弈经济理论研究了在信息不对称条件下四方互动博弈策略的选择,并针对多方博弈的影响因素提出了提高独立审计质量的策略,以期对改进我国上市公司独立审计质量有所裨益.     

An ISO 9001:2000-based framework for realizing quality in small businesses

The purpose of ISO 9001:2000 Quality Management System (QMS) is to provide businesses with a model to grow systematically while assuring the quality of their products. The validity of ISO 9001:2000 QMS stems, largely, from the fact that the best minds worldwide have contributed to its development and maintenance, and the fact that many companies have reported real business gains because of its implementation. Unfortunately, many small businesses fail to survive due to the absence or lack of adequate system for managing quality. An obvious recommendation would be to implement ISO 9001:2000 QMS. Nevertheless, small businesses often cite lack of resources and time as the main reasons for not implementing ISO 9001:2000 QMS.