Confidence Intervals for the Median of a Finite Population Based on the Sign Test

This article presents methods for constructing confidence intervals for the median of a finite population under simple random sampling without replacement, stratified random sampling, and cluster sampling. The confidence intervals, as well as point estimates and test statistics, are derived from sign estimating functions which are based on the well-known sign test. Therefore, a unified approach for inference about the median of a finite population is given.     

Clustering Effects in Unreplicated Factorial Experiments

The analysis of unreplicated factorial designs concentrates much attention since there are no degrees of freedom left to estimate the error variance. In this article, we propose clustering the factorial estimates in two groups, one containing the active effects and one containing the inactive effects. The powerfulness of the proposed method is revealed via a comparative simulation study.     

Are Scandinavian Countries Different? A Comparison of Relative Incomes for Older People in OECD Nations

Recent research has cast some doubt on the consistency of models that isolate Scandinavian countries as different to other nations in terms of egalitarian welfare states. For example, it has been argued that if occupational welfare polices have their contribution to national welfare better accounted for in comparative models, or if there is a focus on specific aspects of welfare coverage, then Scandinavian welfare states look less different to other European countries. Using case‐based methods that try to balance the demand for generalizations and the qualitative integrity of the case, this research examines the specific case of income protection for the older population post‐retirement, to see if Scandinavian countries emerge as consistently different when compared with other OECD nations. Scandinavia can be clearly identified in a separate cluster, but it is not alone and other countries also share its similarities. In particular, Scandinavia emerges in a cluster that provides more income replacement and protection for women. In part, this is reinforced by the high rate of labour participation by women in Scandinavian countries. However, there is little evidence of Scandinavian countries retaining noticeable differences and divergence in income protection policies for men.     

The Importance of Social Embeddedness: Churn Models at Mobile Providers

This article argues the importance of social embeddedness at mobile providers by examining the effects of customers’ network topological properties on churn probability—the probability of a customer switching from one telecommunication provider to another. This article uses data from regional snowball sampling—the only practically feasible network sampling method—to identify groups with significantly different churn ratios for customers with different network topological properties. Clear evidence indicates that individual network characteristics (node‐level metrics) have considerable impact on churn probabilities. The inclusion of network‐related measures in the churn model allows a longer‐term projection of churners and improves the predictive power of the model. With no possibility to carry out repeated sampling, sample stability was checked through simulation results. On the one hand, this article highlights the importance and effectiveness of the provider's tailored marketing campaigns by showing that customers targeted by direct marketing campaigns are less threatened by churn than nontargeted customers. On the other, this article shows that social embeddedness blocks the impact of the very same marketing efforts. This article forwards the idea that social embeddedness, also prevalent in vendor switching, can be extended to understanding the development of professional societies threatened by membership churn.     

中国人口转变地区差异的聚类分析

运用聚类分析方法 ,从总和生育率、平均预期寿命和自然增长率三方面综合了我国 1990年各地区的人口状况 ,将各地区按人口转变完成程度的异同进行了归类 ,并与按生育率转变完成程度的地区划分进行对比。结果显示 ,两种地区类型划分有较大的一致性     

球状星团核的演化

本文用数值方法讨论了中心含有大质量黑洞星团的核在几个作用（蒸发及潮汐）下的演化特征，结果表明：所有的核均会收缩。     

区域经济发展过程中产业的承接、聚集与扩散--基于对福建制鞋业发展的实证分析

发展中国家通过吸引外来投资,发展外向型经济,在推动当地经济发展的同时,却由于外资企业两头在外的经营体系,提高了国内企业进入产业的门槛,加大了产业扩散的难度.福建沿海制鞋业发展表明,承接产业转移,实现产业的扩散和本地化,需要面向国内市场,具有自主开拓市场能力的民营企业的广泛参与.     

空间溢出视角下的生产性服务业集聚与长三角城市群经济增长效率

本文利用空间杜宾模型实证研究了生产性服务业集聚对长三角城市群经济增长效率的影响及空间溢出效应。结果表明,生产性服务业集聚不仅能够显著提升本地区的经济增长效率,还对邻近城市具有正向的空间溢出效应,但这种影响在生产性服务业的细分行业之间存在一定异质性。进一步分析发现,生产性服务业集聚的MAR外部性和Jacobs外部性都有利于长三角城市群经济增长效率的提升,而Porter外部性对经济增长效率具有负面影响。在空间溢出效应方面,Jacobs外部性对经济发展水平相近的城市具有负向溢出效应,Porter外部性对人力资本水平相近的城市具有正向溢出效应。此外,生产性服务业与制造业协同集聚对本地区和人力资本水平相近城市的经济增长效率具有显著促进作用,但对邻近城市和经济发展水平相近城市的经济增长效率因"虹吸效应"而产生一定的抑制作用。这些研究,对如何更有针对性地加快提升长三角城市群经济增长效率,提供了有价值的理论依据。     

中小企业群落结构合理性研究：一个理论探析

企业群落内的企业既竞争又合作 ,竞争能促进创新和产业的发展 ,合作则可以提高资源配置效率、节约交易费用、减少风险等等。尽管合作易伴生机会主义行为 ,但企业群落能得以正常运行 ,是因为企业群落是一个可选择并联耦合系统。企业群落功能的发挥需要企业群落结构具有一定的合理性。并不是只要有相当数量的相关行业的企业集中在一起 ,就能形成企业群落 ,也并不能简单地说企业数量越多越好 ,关键还在于 ,分布在各专业和层次上的企业数量要呈一定的比例