Use of several auxiliary variables in estimating the population mean in a two-occasion rotation pattern

ABSTRACT

This paper addresses the problem of estimation of the population mean on the current (second) occasion in two-occasion successive sampling. Utilizing the readily available information on several auxiliary variables on both occasions and the information on the study variable from the previous occasion, an estimation procedure of the population mean on the current occasion has been proposed. Theoretical properties of the proposed estimator have been investigated. Optimum replacement policy to the proposed estimator has been discussed. The proposed estimator has been compared empirically with the sample mean estimator, when there is no matching and the optimum estimator which is a linear combination of the means of the matched and unmatched portions of the sample at the current occasion. Appropriate recommendations have been made for practical applications.     

"Chain pooling" model selection for two-level fixed effects factorial experiments

As many as three iterated statistical model deletion procedures are considered for an experiment.Population model coeff cients were chosen to simulate a saturated 2⁴experiment having an unfavorable distribution of parameter values.Using random number studies, three model selection strategies were developed, namely, (1) a strategy to be used in anticipation of large coefficients of variation (neighborhood of 65 percent), (2) strategy to be used in anticipation of small coefficients of variation (4 percent or less), and (3) a security regret strategy to be used in the absence of such prior knowledge     

一人公司对外担保的法律思考

为研究一人公司对外担保能力及其限制问题,比较并分析了新旧《公司法》的相关规定。分析认为,一人公司应当具有对外担保的权利能力,能够为其股东以及其他主体提供担保,但债权人在接受担保之前需要对风险作出准确的评估再行决定是否接受此项担保,并通过法人人格否定制度、外部监督制度、债权居次原则和区分原则,避免债权无法实现的问题。     

Covariate Selection for the Semiparametric Additive Risk Model

Abstract.  This paper considers covariate selection for the additive hazards model. This model is particularly simple to study theoretically and its practical implementation has several major advantages to the similar methodology for the proportional hazards model. One complication compared with the proportional model is, however, that there is no simple likelihood to work with. We here study a least squares criterion with desirable properties and show how this criterion can be interpreted as a prediction error. Given this criterion, we define ridge and Lasso estimators as well as an adaptive Lasso and study their large sample properties for the situation where the number of covariates p is smaller than the number of observations. We also show that the adaptive Lasso has the oracle property. In many practical situations, it is more relevant to tackle the situation with large p compared with the number of observations. We do this by studying the properties of the so-called Dantzig selector in the setting of the additive risk model. Specifically, we establish a bound on how close the solution is to a true sparse signal in the case where the number of covariates is large. In a simulation study, we also compare the Dantzig and adaptive Lasso for a moderate to small number of covariates. The methods are applied to a breast cancer data set with gene expression recordings and to the primary biliary cirrhosis clinical data.     

大学城的外部效应及其发展对策研究

大学城"大"的意义不是建立在占地面积广大上而言的,是"大"在教育、科研、人才、信息等资源集中整合、优化配置和立体发展上,实现其在更大范围内、更大程度上对各种资源的合理使用与有效促进区域经济、社会的协调发展。从外部效应的理论范式入手,阐明大学城的外部经济和外部不经济两个方面。最后依据外部效应的矫正机制,提出目前我国大学城建设的对策建议。     

Optimal use of two auxiliary variables in double sampling

Double sampling scheme is used when cheap auxiliary variables may be measured to improve the estimation of a finite population parameter. Several estimators for population mean, ratio of means and variance are available, when two dependent samples are drawn. However, there are few proposals for the case of independent samples. In this paper both cases of dependent and independent samples are dealt with. A general approach for estimating a finite population parameter is given, showing that all the proposed estimators are particular cases of the same general class. The minimum variance bound for any estimator in this class is provided (at the first order of approximation). Furthermore, an optimal estimator which reaches this minimum is found.     

“以学生为中心的主题教学模式”实验研究

通过“以学生为中心的主题教学模式”教改实验测试成绩数据和一系列调查结果的比较分析 ,说明了教学改革对于大学英语课堂教学的效果和学生学习能力的培养有着十分重要的作用     

弱弱联盟:加入WTO后我国中小企业的应对方略

加入WTO以后,面对世界跨国公司和大型企业纷纷结盟、市场竞争日益激烈的形势,处于弱势地位的我国中小企业更应该建立联盟。中小企业建立联盟的基本条件已相对具备。在中小企业之间建立联盟可望产生内、外部溢出效应。     

交际意识是外语教学交际法的灵魂

交际法时下似乎已不怎么"奏效”,对其认识上误区不少,做法上许多已远离初衷.本文从培养学生的交际能力为外语教学的主要目的出发,阐明了交际思想的由来与实质,论述了交际思想两大支柱理论交际能力和学生中心思想.交际思想具有丰富的内涵.交际法不是一种具体的教学方法,而是一种思想观念.要真正有效地实施交际法,必须从转变观念入手,培养和树立各种交际意识.     

院校研究开展外部管理咨询的探讨

目前中国院校研究正从“对象化”走向“实践化”，为数不多的院校研究实践都是一种内部管理咨询活动，是典型的自我研究。为了推进院校研究在中国取得新突破，院校研究在做好内部管理咨询的同时，也要尝试积极开展外部管理咨询，为外校提供专业水平的咨询服务。