Beyond tail median and conditional tail expectation: Extreme risk estimation using tail Lp-optimization

The conditional tail expectation (CTE) is an indicator of tail behavior that takes into account both the frequency and magnitude of a tail event. However, the asymptotic normality of its empirical estimator requires that the underlying distribution possess a finite variance; this can be a strong restriction in actuarial and financial applications. A valuable alternative is the median shortfall (MS), although it only gives information about the frequency of a tail event. We construct a class of tail L^p-medians encompassing the MS and CTE. For p in (1,2), a tail L^p-median depends on both the frequency and magnitude of tail events, and its empirical estimator is, within the range of the data, asymptotically normal under a condition weaker than a finite variance. We extrapolate this estimator and another technique to extreme levels using the heavy-tailed framework. The estimators are showcased on a simulation study and on real fire insurance data.     

Rényi entropy of m-generalized order statistics

Abstract

Characterizing relations via Rényi entropy of m-generalized order statistics are considered along with examples and related stochastic orderings. Previous results for common order statistics are included.     

一种基于区间数判断矩阵的群决策新方法

针对基于区间数判断矩阵的群决策问题,提出了一种群决策新方法.借助于集值统计原理,构造了与区间数判断矩阵群信息等价的具有一定可靠度的确定数判断矩阵,建立了计算这类群信息集结值可靠度的模型,运用和积法对所得新判断矩阵进行处理,得到了一种简便的方案排序方法.最后,通过一个算例验证了该方法的有效性和实用性.     

医学统计学教学改革刍议

针对目前医学统计学教学中存在的问题，从教学内容的调整、教学方法的改进、教学手段的更新等方面入手。探讨如何提高医学统计学的教学质量，目的在于使医学生能够更好地掌握统计学这门学科，成为合格的医学人才。     

Unemployment duration and the measurement of unemployment

We propose a framework in which the welfare bases of various unemployment measures available in the literature can be analyzed and a decomposition of these measures can be made into aggregate unemployment and the concentration of its distribution. A set of axioms for an unemployment measure is then introduced, which relate to the sensitivity of an unemployment measure to the inequality in the distribution of the unemployment. An unemployment measure is derived on the basis of these axioms that captures the distributional considerations in the measurement of unemployment.      

Enrolment in initial courses in statistics: An exploratory study

In January 1981 a questionnaire was sent to 102 universities and colleges in Canada and the United States seeking information on enrolment in initial courses in statistics. That questionnaire has been analyzed and the results are presented in this paper.     

《醒世恒言》被动句式考察

对《醒世恒言》中的被动句式进行分类统计,从用量及结构等方面探讨“于”字式、“见”字式、“为”字式和“为……所”式这些上古汉语传统模式的衰微、“被”字式在近代汉语中的进一步发展以及“教”字式、“与”字式、“吃”字式这些近代汉语才产生的被动式的特点,从而阐述被动句式在近代汉语中的发展概貌。     

统计学发展过程中四次重要的争论及其影响

统计学发展过程中出现过几次重大的争论,这些争论在本质上可以说是一脉相承的。"政治算术"与"国势学"的争论,明确了统计学的学科性质;"描述统计学"与"推断统计学"的争论,构筑了统计学的完整体系;"经典统计学"与"贝叶斯统计学"的争论,带来了统计哲学观的新变化;信念统计学与经典统计学、贝叶斯统计学的争论,使统计推断科学化问题的研究日趋深入。正是通过这些争论完善了现代统计学的思想和方法体系。     

当代大学生媒介消费行为统计分析

当今世界信息传播革命正在兴起,信息技术的迅猛发展推动着大众传播媒介走向现代化。大众传播媒介的发展对大学生的影响尤为深刻。本文拟对当代大学生对大众传播媒介的使用状况作粗浅探索和分析,并试图研究互联网的使用与其它传播媒介的关系。     

Asymptotic distributions for the intervals estimators of the extremal index and the cluster-size probabilities

Under appropriate long range dependence conditions, the point process of exceedances of a stationary sequence weakly converges to a homogeneous compound Poisson point process. This limiting point process can be characterized by the extremal index and the cluster-size probabilities. In this paper we address the problem of estimating these quantities and we consider the intervals estimators introduced in Ferro and Segers [2003. Inference for clusters of extreme values. J. Roy. Statist. Soc. Ser. B 545–556] and in Ferro [2004. Statistical methods for clusters of extreme values. Ph.D. Thesis, Lancaster University]. We establish asymptotic weak convergence to Gaussian random variables and we give their asymptotic variance.