Bayesian estimation of P (Y<X) from Burr-type X model containing spurious observations

We consider the problem of estimating R=P(Y<X) when X and Y are independent Burr-type X random variables. We assume that the sample from each population contains one spurious observation. Bayes estimates are derived for exchangeable and identifiable cases. Monte Carlo simulation is carried out to compare the bias and the expected loss of R.     

Estimation of the intercept parameter for linear regression model with uncertain non-sample prior information

This paper considers alternative estimators of the intercept parameter of the linear regression model with normal error when uncertain non-sample prior information about the value of the slope parameter is available. The maximum likelihood, restricted, preliminary test and shrinkage estimators are considered. Based on their quadratic biases and mean square errors the relative performances of the estimators are investigated. Both analytical and graphical comparisons are explored. None of the estimators is found to be uniformly dominating the others. However, if the non-sample prior information regarding the value of the slope is not too far from its true value, the shrinkage estimator of the intercept parameter dominates the rest of the estimators.     

Measuring the impact of prices on inequality: With applications to Thailand and Korea

This paper develops a new methodology to compute social cost of living indices. These indices indicate whether or not price changes have a favourable (or unfavourable) impact on the welfare of the poor. The indices are derived on the basis of two alternative classes of social welfare functions. The methodology developed in the paper is applied to compute social cost of living indices for Thailand and Korea. The empirical results show that changes in prices have generally affected the poor more adversely than the non-poor.     

果蔬气调包装设计及贮藏期预测

建立了果蔬气调包装的数学模型,通过数值模拟预测包装袋内的气体浓度变化及达到动态平衡时的气体浓度,给出了包装材料的确定方法及不同气调参数下果蔬气调包装贮藏期的预测方法.以黄桃为研究对象,测定了5℃和25℃下自发气调包装的气体浓度变化规律,进行了0℃及体积分数为2%O2、5%CO2初始浓度条件下的主动气调包装贮藏实验.实验结果验证了数学模型预测结果的正确性.     

有非负约束的线性模型

讨论有非负约束的线性模型的估计，证明了此模型可以用矩阵的消去变换来求解，主要应用于可靠性统计分析中。     

一类无平方因子数的k次方和

拓广了无平方因子数ｋ次方和的结果，得到一类无平方因子数ｋ次方和的估计式．     

Local model uncertainty and incomplete-data bias (with discussion)

Summary.  Problems of the analysis of data with incomplete observations are all too familiar in statistics. They are doubly difficult if we are also uncertain about the choice of model. We propose a general formulation for the discussion of such problems and develop approximations to the resulting bias of maximum likelihood estimates on the assumption that model departures are small. Loss of efficiency in parameter estimation due to incompleteness in the data has a dual interpretation: the increase in variance when an assumed model is correct; the bias in estimation when the model is incorrect. Examples include non-ignorable missing data, hidden confounders in observational studies and publication bias in meta-analysis. Doubling variances before calculating confidence intervals or test statistics is suggested as a crude way of addressing the possibility of undetectably small departures from the model. The problem of assessing the risk of lung cancer from passive smoking is used as a motivating example.     

软件项目工作量预估系统的研究与实现

采用了一种改进的软件成本估算方法——结构化成本模型COCOMOII结合功能点模型和多元回归算法来进行软件项目工作量的预估，以便降低对工作量估算的结果偏差．介绍了基于该算法设计的软件项目工作量预估系统的部分关键实现技术．系统采用浏览器／服务器模式及JSP＋Java＋MySql的架构实现，由于充分利用了网络的便捷和信息量大的特点，保证了多元回归算法中对样本数量的要求，使估算值更接近实际结果．     

Getting the offer: Sex discrimination in hiring

The hiring process is currently the least understood aspect of the employment relationship. It may be the most important for understanding the broad processes of stratification with allocation of demographic groups to jobs and firms. The lack of knowledge is due to difficulty of assembling data on the processes that occur at the point of hire. Against this background we analyze data on all applicants to positions in one of the largest Scandinavian banks in 1997–1998, providing what we believe to be the first study using applicant pool data and information about extended offers in a private-sector European firm, adding to the record of about half a dozen such U.S. studies. The hiring agents in the organization are fully conscious and concerned about the nonconscious biases and gender schemas they carry when making hiring decisions. Their effects on hiring are considered to be beyond dispute: women are at a clear disadvantage. For actual hiring practices we found that the opposite is true: women are not at a disadvantage and may even be at an advantage in getting offers. Two organizational practices may lead to female advantage. The hiring agents had been educated about the role of nonconscious biases, which perhaps mitigated their effects. But they had also been instructed to search actively for qualified females in the applicant pool. With no qualified females in the first pass, they go through the pool a second and third time hoping to find one. We discuss reasons why the interpretations and meanings the hiring agents attribute to the hiring process are at odds with what actually occurs.     

Nonparametric estimation of a change in defect intensity

Summary.  In an important class of problems involving mixture distributions, interest focuses on the mixture proportions, considering other possible parameters as nuisance parameters. We formulate a new variation on such problems that arose in a study on the link between the number of cells in a charge-coupled detector image sensor that turned defective because of cosmic radiation and the storage conditions of such sensors. In this variation, the component densities are bivariate, there are two classes and only a subset of the mixture proportions is of relevance. We propose a nonparametric method to estimate the relevant subset of the proportions and apply our method to the data in our study.