Tests for zero inflation in a bivariate zero‐inflated Poisson model

The score test statistics for testing zero inflation and covariance parameter are proposed in the bivariate zero‐inflated Poisson (BZIP) regression model. The Monte Carlo studies show that the score test and likelihood ratio test for testing zero inflation underestimate the nominal significance level, while the score test for covariance parameter keeps the significance level close to the nominal one. To overcome this nominal level underestimation, we propose a bootstrap method of the score test for the testing problem of zero inflation. An empirical example with covariates is provided to illustrate the results. In addition, score test for zero inflation is also proposed in the BZIP model, which allows a flexible dependence structure using copula.     

Relative Efficiency of the Fuzzy p-Value Approach to Hypothesis Testing

In missing data problems, it is often the case that there is a natural test statistic for testing a statistical hypothesis had all the data been observed. A fuzzy  p -value approach to hypothesis testing has recently been proposed which is implemented by imputing the missing values in the "complete data" test statistic by values simulated from the conditional null distribution given the observed data. We argue that imputing data in this way will inevitably lead to loss in power. For the case of scalar parameter, we show that the asymptotic efficiency of the score test based on the imputed "complete data" relative to the score test based on the observed data is given by the ratio of the observed data information to the complete data information. Three examples involving probit regression, normal random effects model, and unidentified paired data are used for illustration. For testing linkage disequilibrium based on pooled genotype data, simulation results show that the imputed Neyman Pearson and Fisher exact tests are less powerful than a Wald-type test based on the observed data maximum likelihood estimator. In conclusion, we caution against the routine use of the fuzzy  p -value approach in latent variable or missing data problems and suggest some viable alternatives.     

经济增长和制度性变革对税收收入影响的分析

利用1978~2006年的年度数据,建立时序模型考察了税收与经济增长之间的均衡关系,并利用结构突变理论对税收数据的生成过程进行了分析。指出,税收收入与经济增长具有长期均衡关系,但GDP的变动不能显著解释税收收入的短期波动,而制度性因素尤其是税务机关的征管技术变革对税收收入的短期波动具有显著的解释作用。     

三波形梁钢护栏连接过渡段的有限元仿真模拟试验

文章从高速公路交通事故的统计资料分析了现有半刚性与刚性护栏连接过渡段存在的问题，利用有限元方法对汽车高速碰撞护栏连接过渡段进行仿真模拟试验，提出全新的护栏过渡段设计方法。     

高校计算机基础课程考核体系的改革与创新

目前高校的计算机基础课程考核体系中存在诸多问题,本文结合计算机基础课程的特点,研究与探索新的注重实践与学生实际动手能力的考核体系与考试方式,将日常教学、实验与随机申请、网上自动考试有机结合起来,提出科学、合理并符合高校实际的计算机基础课程考核体系。     

Estimating average economic growth in time series data with persistency

This paper studies estimation of average economic growth in time series models with persistency. In particular, a joint estimation of the trend coefficient and the autoregressive parameter is considered. An analysis on the proposed estimator is provided. Our analysis is also extended to the case with general disturbance distributions. A nonlinear M estimator and a class of partially adaptive M estimators which adapt themselves with respect to a measure of the tailthickness are considered. The joint estimator and its partially adapted version are compared with several conventional estimators. Monte Carlo experiments indicate that the proposed estimators have good finite sample performance. We use the proposed estimation procedure to estimate the growth rates for real GNP and consumer price index in 40 countries.     

大学英语考试体系:问题与改革

现行大学英语考试体系存在着包括考核能力项目不完整、考核的知识点怪僻等缺陷。为实现培养目标, 大学英语考试改革势在必行,应逐渐完善考试项目,试题设计力求客观,满足实际交际需要。     

抗芯吸涤纶工业长丝的研制

抗芯吸添加剂与纺丝油剂按一定比例混合后附着在涤纶工业长丝表面，能有效地增强纤维的抗芯吸能力。文章探讨了抗芯吸剂在涤纶工业长丝上的附着原理和方式，以及抗芯吸剂附着量、热处理条件对涤纶工业长丝抗芯吸性能的影响。     

石油测试仪器的可靠性研究

从石油测试仪器的特点出发,探讨了其可靠性的意义。分析了石油测试仪器与其它电子产品的可靠性试验方法的不同特性,使其设计方案更加合理。