New approximate confidence intervals for the difference between two Poisson means and comparison

The problem of estimating the difference between two Poisson means is considered. A new moment confidence interval (CI), and a fiducial CI for the difference between the means are proposed. The moment CI is simple to compute, and it specializes to the classical Wald CI when the sample sizes are equal. Numerical studies indicate that the moment CI offers improvement over the Wald CI when the sample sizes are different. Exact properties of the CIs based on the moment, fiducial and hybrid methods are evaluated numerically. Our numerical study indicates that the hybrid and fiducial CIs are in general comparable, and the moment CI seems to be the best when the expected total counts from both distributions are two or more. The interval estimation procedures are illustrated using two examples.     

Exceedance probabilities for parametric control charts

Common control charts assume normality and known parameters. Quite often, these assumptions are not valid and large relative errors result in the usual performance characteristics such as the false alarm rate or the average run length. A fully nonparametric approach can form an attractive alternative but requires more Phase I observations than usually available. Sufficiently general parametric families then provide realistic intermediate models. In this article, the performance of charts based on such families is considered. Exceedance probabilities of the resulting stochastic performance characteristics during in-control are studied. Corrections are derived to ensure that such probabilities stay within prescribed bounds. Attention is also devoted to the impact of the corrections for an out-of-control process. Simulations are presented both to illustrate and to demonstrate that the approximations obtained are sufficiently accurate for practical usage.     

继承与创新：沃尔兹新现实主义理论定位再探讨

肯尼思·沃尔兹的新现实主义是国际政治研究的里程碑,但学界对这一里程碑含义的理解可能存在偏差。这一理论不是国际政治研究科学化的起点,而是对古典现实主义核心论点的历史性再诠释。沃尔兹和其他古典现实主义者一样认为人的理性能力存在限度,相信实力对比是进行利益划分的客观依据,劝告政治家遵行责任伦理。古典现实主义者与沃尔兹之间的差异并没有想象的大,古典现实主义者也强调安全,他们发现国际政治中存在着安全困境,追求过多权力会导致不安全,国家追求权力应适可而止。古典现实主义者还发现世界政治中因果关系非常复杂,事件的结果绝少和当事者的动机一致,“事与愿违”是政治中的常态,这与沃尔兹强调的“系统效应”相似。新古典现实主义者试图将沃尔兹的理论进一步科学化,他们希望结合结构变量与单元变量,提出更科学的理论解释、预测国家的行为,这不仅误解了沃尔兹,也背离了现实主义传统。     

劳工NGO对农民工权益保障的价值和限度

在当代中国,政府无论是对劳资事务的监管还是保障农民工合法权益行动,存在许多局限性,均会出现政府失灵的问题,它需要劳工NGO予以回应。而劳工NGO参与社会公共事务治理,尤其是其人性化志愿服务能有效地为农民工提供社会网络支持、情感支持,提升其法律意识,降低可能的暴力维权行动,这对政府劳资事务治理和实现社会稳定有积极意义。但现行非政府组织政策环境限制其参与保障农民工合法权益的活动,同时,劳工NGO大多缺少合法身份和资源,制约其与政府良性互动,降低其作用的发挥。     

Hybrid-based confidence intervals for the ratio of two treatment means in the over-dispersed Poisson data

In many clinical trials and epidemiological studies, comparing the mean count response of an exposed group to a control group is often of interest. This type of data is often over-dispersed with respect to Poisson variation, and previous studies usually compared groups using confidence intervals (CIs) of the difference between the two means. However, in some situations, especially when the means are small, interval estimation of the mean ratio (MR) is preferable. Moreover, Cox and Lewis [4 D.R. Cox and P.A.W. Lewis, The Statistical Analysis of Series of Events, Methuen, London, 1966.[Crossref] , [Google Scholar]] pointed out many other situations where the MR is more relevant than the difference of means. In this paper, we consider CI construction for the ratio of means between two treatments for over-dispersed Poisson data. We develop several CIs for the situation by hybridizing two separate CIs for two individual means. Extensive simulations show that all hybrid-based CIs perform reasonably well in terms of coverage. However, the CIs based on the delta method using the logarithmic transformation perform better than other intervals in the sense that they have slightly shorter interval lengths and show better balance of tail errors. These proposed CIs are illustrated with three real data examples.     

菲律宾条约界限的性质刍议——以条约界限的形成、演变与确立为中心

菲律宾条约界限是现代菲律宾国家领土形成的重要法理与历史依据,划定了菲律宾领土的基本范围。其前身是1898年美西《巴黎和约》提出的"巴黎和约线",后经三次局部变动,最终演变成菲律宾条约界限并固化,而不能再外扩至其他岛礁。条约界限正式构建了美属菲律宾的疆界,这一领土范围为独立后的菲律宾所继承。菲律宾宣称对南沙群岛的部分岛礁和黄岩岛享有主权,根本是站不住脚的。     

Bayesian X̄ control limits for exponentially distributed measurements

This article deals with the construction of an X? control chart using the Bayesian perspective. We obtain new control limits for the X? chart for exponentially distributed data-generating processes through the sequential use of Bayes’ theorem and credible intervals. Construction of the control chart is illustrated using a simulated data example. The performance of the proposed, standard, tolerance interval, exponential cumulative sum (CUSUM) and exponential exponentially weighted moving average (EWMA) control limits are examined and compared via a Monte Carlo simulation study. The proposed Bayesian control limits are found to perform better than standard, tolerance interval, exponential EWMA and exponential CUSUM control limits for exponentially distributed processes.     

“肯定列表制度”对中国输日农产品的经济效应

通过运用局部均衡模型研究发现,“肯定列表制度”在短期会使中国贸易福利减少,贸易条件恶化,存在负经济效应;在中长期则有利于出口企业提高技术水平,存在贸易促进作用。应用中国农产品最新出口月度统计数据进行实证分析,并选取代表产品——烤鳗,用计量经济学方法和EVIEWS软件建立多元线性回归模型。在剔除相关因素的影响后,“肯定列表制度”的实施使中国对目烤鳗出口数量减少607．6361个单位,短期负面影响显著。     

A note on some modified Pulak and Al-Sultan's model

Pulak and Al-Sultan presented a rectifying inspection plan applying in the determination of optimum process mean. However, they did not point out whether the non-conforming items in the sample of accepted lot are replaced or eliminated from the lot and neglected the quality loss within specification limits. In this paper, we further propose the modified Pulak and Al-Sultan model with quadratic quality loss function. There are four cases considered in the modified model: (1) the non-conforming items in the sample of accepted lot are neither replaced nor eliminated from the lot; (2) the non-conforming items in the sample of accepted lot are not replaced but are eliminated from the lot; (3) the non-conforming items in the sample of accepted lot are replaced by conforming ones; (4) the non-conforming items in the sample of accepted lot are replaced by non-inspected items. The numerical results and sensitivity analysis of parameters show that their solutions are slightly different.     

Confidence intervals for a two-parameter exponential distribution: One- and two-sample problems

The problems of interval estimating the mean, quantiles, and survival probability in a two-parameter exponential distribution are addressed. Distribution function of a pivotal quantity whose percentiles can be used to construct confidence limits for the mean and quantiles is derived. A simple approximate method of finding confidence intervals for the difference between two means and for the difference between two location parameters is also proposed. Monte Carlo evaluation studies indicate that the approximate confidence intervals are accurate even for small samples. The methods are illustrated using two examples.