Random effects regression mixtures for analyzing infant habituation

Random effects regression mixture models are a way to classify longitudinal data (or trajectories) having possibly varying lengths. The mixture structure of the traditional random effects regression mixture model arises through the distribution of the random regression coefficients, which is assumed to be a mixture of multivariate normals. An extension of this standard model is presented that accounts for various levels of heterogeneity among the trajectories, depending on their assumed error structure. A standard likelihood ratio test is presented for testing this error structure assumption. Full details of an expectation-conditional maximization algorithm for maximum likelihood estimation are also presented. This model is used to analyze data from an infant habituation experiment, where it is desirable to assess whether infants comprise different populations in terms of their habituation time.     

Bayesian analysis of mixture modelling using the multivariate t distribution

A finite mixture model using the multivariate t distribution has been shown as a robust extension of normal mixtures. In this paper, we present a Bayesian approach for inference about parameters of t-mixture models. The specifications of prior distributions are weakly informative to avoid causing nonintegrable posterior distributions. We present two efficient EM-type algorithms for computing the joint posterior mode with the observed data and an incomplete future vector as the sample. Markov chain Monte Carlo sampling schemes are also developed to obtain the target posterior distribution of parameters. The advantages of Bayesian approach over the maximum likelihood method are demonstrated via a set of real data.     

中国碳排放库兹涅茨曲线存在性研究

经济增长与环境恶化之间的矛盾直接推动了碳排放库兹涅茨曲线的研究。本文基于1995-2009年中国省际碳排放面板数据,利用面板协整和误差修正模型对中国碳排放库兹涅茨曲线的存在性进行实证研究,结果发现：动态固定效应下的面板误差修正模型最优,碳排放与经济增长间存在长期稳定的倒U型关系,拐点为人均国内生产总值29847.29元,且存在短期误差修正机制;与权威机构时序数据回归结果比较,动态面板模型结果具有稳健性。     

“以支定收”还是“以收定支”:我国财政收支关系的实证研究

通过对我国财政收入与支出的时序变量建立协整与误差修正模型,实证研究我国的财政收支关系中到底是以支定收还是以收定支,确定这种收支之间的因果关系对采取财政政策的借鉴意义。研究将回答,我国财政收入是财政支出之间是单向格兰杰因还是双向格兰杰因,抑或互非因果关系,并在此基础上指出财政政策的作用方向,为真正建立符合的现代市场经济的财政观提供经验证据。     

Skew-normal factor analysis models with incomplete data

Traditional factor analysis (FA) rests on the assumption of multivariate normality. However, in some practical situations, the data do not meet this assumption; thus, the statistical inference made from such data may be misleading. This paper aims at providing some new tools for the skew-normal (SN) FA model when missing values occur in the data. In such a model, the latent factors are assumed to follow a restricted version of multivariate SN distribution with additional shape parameters for accommodating skewness. We develop an analytically feasible expectation conditional maximization algorithm for carrying out parameter estimation and imputation of missing values under missing at random mechanisms. The practical utility of the proposed methodology is illustrated with two real data examples and the results are compared with those obtained from the traditional FA counterparts.     

中国教育生产力和科技生产力发展关系的实证研究——基于误差修正模型

马克思在其著作中研究了教育和科技作为两个重要因素在生产力发展过程中所起到的作用。教育生产力和科技生产力都是生产力系统的重要组成部分,两者之间存在着内在的、本质的、必然的关系。通过构造误差修正模型,分析中国教育生产力和科技生产力发展之间的长期稳定关系和短期协调机制,对于认识我国教育事业与科技事业发展的内在规律、更好的促进教育生产力和科技生产力的发展具有重要意义。     

货币政策传导机制有效性的实证研究

文章选取货币供应量和金融机构年末贷款余额作为货币政策的中介指标变量,以经济增长作为货币政策的最终目标变量,运用动态计量经济学理论,通过对变量的单位根检验,协整检验和因果关系检验,对1978~2004年的数据采用EG两步法建立误差修正模型。研究表明货币政策传导存在明显的时滞,而且货币供应量增长率与贷款余额增长率相比对经济增长率的影响更显著。     

进口对中国经济增长驱动作用的实证分析

文章通过理论与实证分析阐述了进口对中国经济增长的驱动作用。理论上主要从当前的国际环境及中国的国情两方面论述了适当增加进口的必要性和可行性。实证上则是利用动态分布滞后(ADL)模型对进口与GDP关系进行协整分析并通过建立误差修正模型(ECM)进一步说明进口对中国经济增长的促进作用。最后根据以上分析提出建议:中国应适当增加进口以解决当前存在的贸易问题。     

我国财政收入与GDP的动态关系研究

一国财政收入与国内生产总值(GDP)之间有着高度的相关关系。普通的静态回归和一般的动态回归虽然可以把它们之间的关系展示出来,然而却各有缺陷。本文旨在通过建立误差修正模型来对我国财政收入与GDP之间的关系进行拟合,以揭示它们之间的长期和短期关系,并且在此基础上给出提高财政收入增长速度的具体措施。     

中美棉花期货价格引导和均衡关系的实证分析

对中国棉花期货上市至实证结束期间796个价格数据,运用Eviews软件的协整分析、Granger因果检验、误差修正模型和方差分解法,实证检验了中国和美国棉花期货价格之间的关系,结果表明:中美棉花期货价格之间的协整关系成立,两者具有显著的长期稳定关系;中美棉花期货价格间存在显著的相互引导关系;短期内美国棉花期货价格变动是中国棉花期货价格变动Granger意义上的原因;中国期货价格虽受到美国棉花期货价格的影响,但具有较强的独立性。