SEMI-PARAMETRIC ANALYSIS OF COVARIANCE UNDER DEPENDENCE CONDITIONS WITHIN EACH GROUP

Consider the problem of covariance analysis based on regression models whose regression function is the sum of a linear and a non-parametric component. We propose a parametric and a non-parametric statistical test to compare the effects of the linear and non-parametric components, respectively, on the response variable in   L ≥ 2  groups. Serially correlated errors within each group are allowed. The first (second) test compares the differences between the estimates of the parametric (non-parametric) components of each group by means of a Mahalanobis  ( L ²)  distance. The asymptotic distribution of each statistic under the null hypothesis is obtained. A modest simulation study and an application to a real data set illustrate our methodology.     

我国上市公司资本结构调整行为研究

以620家中国上市公司1998-2005年间财务数据为样本,对其资本结构动态调整行为进行实证研究。通过采用固定效应方法对部分调整模型进行估计,验证了该理论对中国股票市场的解释能力。结果表明我国上市公司的确以每年大约40%的速度缩小真实值与目标值之间的差距,调整的方式主要是通过负债的变动。公司其他的特征变量如资产收益率、资产折旧率、公司规模和股权结构等都对动态调整过程有显著的影响。     

基于PLS的R＆D投入效果的实证分析

运用偏最小二乘(PLS)回归方法,建立Cobb-Douglas生产函数,分析了影响天津市经济发展的各投入要素,在投入向量中引入研究与发展存量T,并充分考虑了研究与发展投资效用的滞后性与长期性。对天津市研究与发展投资收益与边际收益进行分析计算,认为加大研究与发展投入力度是提高天津市科技综合竞争力,实现经济持续稳定、快速增长的最有效途径,为天津市制订不确定条件下研究与发展风险投资战略提供有益的参考。     

中国农村金融体制改革的最优路径选择

从系统论的观点出发,并利用“樊、胡福利指数模型”对我国农村金融体制改革路径进行了分析、验证。研究表明:我国现行农村金融体制所遵循的“循序渐进”改革路径造成了农村金融体制内部不协调发展。受“不协调成本”的影响,我国农村金融的功能非但没有在改革中更趋完善,反而出现了萎缩。建议我国农村金融体制选择“平行推进”的改革路径。     

A Bayesian Non-parametric Comparison of Two Treatments

In this paper we present a Bayesian non-parametric analysis of survival time data, involving information from two types of treatment. We present an easy to compute Bayes factor comparing two model assumptions: no treatment difference and treatment difference and use this to model summaries for each of the two treatments, in particular predictive distributions.     

Cox Regression with Covariate Measurement Error

This article deals with parameter estimation in the Cox proportional hazards model when covariates are measured with error. We consider both the classical additive measurement error model and a more general model which represents the mis-measured version of the covariate as an arbitrary linear function of the true covariate plus random noise. Only moment conditions are imposed on the distributions of the covariates and measurement error. Under the assumption that the covariates are measured precisely for a validation set, we develop a class of estimating equations for the vector-valued regression parameter by correcting the partial likelihood score function. The resultant estimators are proven to be consistent and asymptotically normal with easily estimated variances. Furthermore, a corrected version of the Breslow estimator for the cumulative hazard function is developed, which is shown to be uniformly consistent and, upon proper normalization, converges weakly to a zero-mean Gaussian process. Simulation studies indicate that the asymptotic approximations work well for practical sample sizes. The situation in which replicate measurements (instead of a validation set) are available is also studied.     

Inter‐Organizational Fit,Relationship Management Capability,and Collaborative Performance within a Humanitarian Setting

Donors and governments are increasingly calling for more collaborative relationships between humanitarian organizations (HOs), to improve the efficiency and effectiveness of humanitarian operations by exchanging information, knowledge, and resources. This study examines the relative efficacy of partners' characteristics (i.e., compatibility and resource complementarity) and partners' relationship management capability on collaborative relationships, incorporating mutual trust and reciprocal commitment as two mediator constructs. We use Partial Least Squares to examine the proposed hypotheses using a sample of 191 respondents. Data are collected through a web‐survey of international humanitarian non‐governmental organizations (NGOs) in countries across Africa, Asia, and South America. The results reveal that (i) resource complementarity and relationship management capability are significant factors influencing collaborative performance through their effects on partners' mutual trust and reciprocal commitment, and that (ii) partners' compatibility (i.e., missions, values, and operational methods) does not significantly drive success or failure of collaboration between international NGOs. These results suggest that given the present diversity of HOs' characteristics, the success of collaboration is associated with the partners' level of understanding of each other's objectives, operations, and values, and to the extent to which organizations efficiently communicate and coordinate their joint activities. The managerial implications of the findings are also discussed.     

一个函数不等式的推广和应用

将一个一元函数不等式推广到二维情形，并给出在初等不等式方面的几个应用。     

Root-n-consistent Estimation in Partial Linear Models with Long-memory Errors

We consider estimation of β in the semiparametric regression model y ( i ) - x ^T( i )β + f ( i / n ) + ε( i ) where x ( i ) = g ( i )/ n ) + e ( i , f and g are unknown smooth functions and the processes ε( i ) and e ( i ) are stationary with short- or long-range dependence. For the case of i.i.d. errors, Speckman (1988) proposed a √ n –consistent estimator of β. In this paper it is shown that, under suitable regularity conditions, this estimator is asymptotically unbiased and √ n –consistent even if the errors exhibit long-range dependence. The orders of the finite sample bias and of the required bandwidth depend on the long-memory parameters. Simulations and a data example illustrate the method     

Bayes linear computation: concepts,implementation and programs

We demonstrate how Bayes linear methods, based on partial prior specifications, bring us quickly to the heart of otherwise complex problems, giving us natural and systematic tools for evaluating our analyses which are not readily available in the usual Bayes formalism. We illustrate the approach using an example concerning problems of prediction in a large brewery. We describe the computer language [B/D] (an acronym for beliefs adjusted by data), which implements the approach. [B/D] incorporates a natural graphical representation of the analysis, providing a powerful way of thinking about the process of knowledge formulation and criticism which is also accessible to non-technical users.