On the Similarity Structure of Order Statistics

In this article, we address the similarity structure between pairs of order statistics of an identically distributed independent random variables X₁,…, X_n. The overlapping coefficient (Δ) of Weitzman (1970 Weitzman , M. S. ( 1970 ). Measures of overlap of income distributions of white and Negro families in the United States . Technical Paper No. 22 , Washington , D.C. , U.S.A : Department of Commerce, Bureau of Census . [Google Scholar]), is used to assess the degree of similarity or closeness between pairs of order statistics. It appears that the degree of the similarity between any of such pairs is independent of the parent distribution. Using this notion, it is shown that for i < j, the degree of similarity between distributions of the ith and the jth order statistics decreases as i and j sunder. Some possible biometric applicability of the value of Δ are explored. In particular, the use of this measure in estimation of the number of possible strata, subgroups or natural subdivisions in a population are suggested.     

Dirichlet models for square contingency tables

We consider the square contingency tables which arise when the same method of classification is applied twice. The hypothesis of marginal homogeneity is then relevant! and can be tested by various methods Models are discussed which contain marginal homogeneity as a special case. They include a class based on univariate and bivariate Dirichlet distributions. The question of ordered categories is briefly discussed. Applications are made to data on unaided distance vision.     

A Nonrandomized,Nonconservative Version of the Fisher Exact Test

The Fisher exact test has been unjustly dismissed by some as ‘only conditional,’ whereas it is unconditionally the uniform most powerful test among all unbiased tests, tests of size α and with power greater than its nominal level of significance α. The problem with this truly optimal test is that it requires randomization at the critical value(s) to be of size α. Obviously, in practice, one does not want to conclude that ‘with probability x the we have a statistical significant result.’ Usually, the hypothesis is rejected only if the test statistic's outcome is more extreme than the critical value, reducing the actual size considerably.

The randomized unconditional Fisher exact is constructed (using Neyman–structure arguments) by deriving a conditional randomized test randomizing at critical values c(t) by probabilities γ(t), that both depend on the total number of successes T (the complete-sufficient statistic for the nuisance parameter—the common success probability) conditioned upon.

In this paper, the Fisher exact is approximated by deriving nonrandomized conditional tests with critical region including the critical value only if γ (t) > γ₀, for a fixed threshold value γ₀, such that the size of the unconditional modified test is for all value of the nuisance parameter—the common success probability—smaller, but as close as possible to α. It will be seen that this greatly improves the size of the test as compared with the conservative nonrandomized Fisher exact test.

Size, power, and p value comparison with the (virtual) randomized Fisher exact test, and the conservative nonrandomized Fisher exact, Pearson's chi-square test, with the more competitive mid-p value, the McDonald's modification, and Boschloo's modifications are performed under the assumption of two binomial samples.     

Continuous Time Wishart Process for Stochastic Risk

Risks are usually represented and measured by volatility–covolatility matrices. Wishart processes are models for a dynamic analysis of multivariate risk and describe the evolution of stochastic volatility–covolatility matrices, constrained to be symmetric positive definite. The autoregressive Wishart process (WAR) is the multivariate extension of the Cox, Ingersoll, Ross (CIR) process introduced for scalar stochastic volatility. As a CIR process it allows for closed-form solutions for a number of financial problems, such as term structure of T-bonds and corporate bonds, derivative pricing in a multivariate stochastic volatility model, and the structural model for credit risk. Moreover, the Wishart dynamics are very flexible and are serious competitors for less structural multivariate ARCH models.     

Influence in covariance structure analysis: with an application to confirmatory factor analysis

Influence functions are derived for the parameters in covariance structure analysis, where the parameters are estimated by minimizing a discrepancy function between the assumed covariance matrix and the sample covariance matrix. The case of confirmatory factor analysis is studied precisely with a numerical example. Comparing with a general procedure called one-step estimation, the proposed procedure has two advantages:1) computing cost is cheaper, 2) the property that arbitrary influence can be decomposed into a fi-nite number of components discussed by Tanaka and Castano-Tostado(1990) can be used for efficient computing and the characterization of a covariance structure model from the sensitivity perspective. A numerical comparison is made among the confirmatory factor analysis and some procedures of ex-ploratory factor analysis by using the decomposition mentioned above.     

我国上市公司资本结构调整速度及其影响因素研究

通过对我国上市公司的资本结构调整速度和影响因素进行深入分析,结果发现我国上市公司的资本结构调整速度存在着显著的行业差异性,垄断行业上市公司的资本结构最优化程度最低,资本结构调整低于平均水平,而竞争激烈行业由于竞争的压力,资本结构寻求优化的程度较高,向最优结构调整的速度也较快。另外,我国上市公司资本结构向最优化的调整过程受到企业自身微观因素和宏观经济因素的重要影响,企业自身的微观因素主要包括公司的财务状况、公司治理结构、当前的资本结构,而宏观因素主要是利率和通货膨胀率,GDP对调整过程影响并不显著。     

资源结构优化与县域经济增长

资源的丰富程度及资源结构的优化度直接制约着县域经济的长期增长。立足我国县域社会和人文资源稀缺、经济缺乏新的增长点的现状,突破路径依赖寻求最佳经济增长模式、积极培育和整合社会人文资源以及实施竞争优势战略,是优化县域资源结构、推动县域经济持续增长的科学选择。     

金融制度变革与县域产业结构发展——内蒙古县域经济视角

按照商业银行经营管理的原则和城市化、集约化的市场定位要求,代表国家利益的四大国有商业银行面对大量坏帐开始逐步放弃对欠发达县域经济的支持模式,使县域政府主导的产业发展模式面临着调整的困境。在这种困境中,县域产业结构调整实际上就是企业的衰败所带动的行业的衰败甚至消亡,在缺乏外部资金的条件下,旗县政府和企业只能被动接受现实。     

寡占型企业技术创新竞争的模型分析

在现代技术创新过程中,以寡占企业为主体的市场结构发挥着越来越显著的作用。这种寡占型市场结构是一种松散型寡占结构,有利于保持适度的技术创新速度。在现代经济条件下,寡占型企业的合作创新已成为越来越重要的技术创新形式。     

社会转型期农村家庭养老功能弱化的原因解析——基于陇东南L村的调查

甘肃省东南部L村的个案表明,社会转型时期农村家庭养老功能日渐弱化,其原因在于农村人口流动的持续时问延长与范围扩大,家庭的小型化与核心家庭剧增,老人养老与子女赡养观念的分歧。为此,有必要寻求符合时代发展的新型养老模式。