Pareto Regression: A Bayesian Analysis

Abstract

In this article, a new model is presented that is based on the Pareto distribution of the second kind, when the location parameter depends on covariates as well as unobserved heterogeneity. Bayesian analysis of the model can be performed using Markov Chain Monte Carlo techniques. The new procedures are illustrated in the context of artificial data as well as international output data.     

工资收入差异的解释：基于分位数回归的经验研究

利用CHNS2006年的数据,通过分位数回归方法从教育回报率、性别和工作部门的差异三个方面对中国工资收入差异进行研究,得出与以往研究不同的结论。结果表明：教育回报率在工资收入分布上的变动趋势是不定的。在工资收入分布的两端,大专以上学历对工资收入差距的影响相对较大。对不同性别间工资收入差异的分解表明劳动力市场上存在明显的性别歧视,而对部门间工资差异的分解表明在整个工资分布区间,这种差异呈倒＂U＂型走势。     

分位数回归与上证综指VaR研究

把极端分位数所具有的行为特征应用到VaR的研究中,建立上海股市收益率的条件分位数回归模型,描述其在极端分位数下的变化趋势。同时选取适当的尾部模型,并在此基础之上应用外推法预测非常极端分位数下的条件VaR,并与直接由分位数回归模型预测的结果进行比较。结果表明：两种方法得到的结果变化趋势都是一致的,由外推法预测的结果相对小一些。     

A New Regression Model: Modal Linear Regression

The mode of a distribution provides an important summary of data and is often estimated on the basis of some non‐parametric kernel density estimator. This article develops a new data analysis tool called modal linear regression in order to explore high‐dimensional data. Modal linear regression models the conditional mode of a response Y given a set of predictors x as a linear function of x . Modal linear regression differs from standard linear regression in that standard linear regression models the conditional mean (as opposed to mode) of Y as a linear function of x . We propose an expectation–maximization algorithm in order to estimate the regression coefficients of modal linear regression. We also provide asymptotic properties for the proposed estimator without the symmetric assumption of the error density. Our empirical studies with simulated data and real data demonstrate that the proposed modal regression gives shorter predictive intervals than mean linear regression, median linear regression and MM‐estimators.     

Frequency of Selecting Noise Variables in Subset Regression Analysis: A Simulation Study

This article presents the results of a simulation study of variable selection in a multiple regression context that evaluates the frequency of selecting noise variables and the bias of the adjusted R ² of the selected variables when some of the candidate variables are authentic. It is demonstrated that for most samples a large percentage of the selected variables is noise, particularly when the number of candidate variables is large relative to the number of observations. The adjusted R ² of the selected variables is highly inflated.     

Ridge Regression: Degrees of Freedom in the Analysis of Variance

It appears to be common practice with ridge regression to obtain a decomposition of the total sum of squares, and assign degrees of freedom, according to established least squares theory. This discussion notes the obvious fallacies of such an approach, and introduces a decomposition based on orthogonality, and degrees of freedom based on expected mean squares, for non-stochastic k.     

A Dynamic Analysis of Prices in the U.S. Rice Marketing Channel

Granger causality tests and dynamic multipliers are used to explore the dynamic relationship among prices in the U.S. rice marketing channel. The dynamic multipliers provide information about the speed and magnitude of dynamic price adjustments that is not provided by the Granger causality tests. This information is shown to be useful in explaining the underlying economic relationship among the time series of prices.     

分量回归下的中国股市价量关系研究

本文用分量回归的方法来分析中国股市收益率和成交量关系。实证结果发现中国股市具有“价量齐扬”和“价跌量缩”的现象,但前者在接近最大涨幅时减弱,而后者在接近最大跌幅时增强。然若采用传统的OLS方法分析,则无法发现这种不对称性。对于此涨跌幅下的价量关系不对称特征,我们认为可能的原因是股市的卖空限制使投资人无法对市场信息（尤其是负面信息）充分反应,因此造成正负收益率与成交量之间的不对称关系。     

Jackknifing the Ridge Regression Estimator: A Revisit

Singh et al. (1986 Singh, B., Chaubey, Y.P., Dwivedi, T.D. (1986). An almost unbiased ridge estimator. Sankhya B48: 34236. [Google Scholar]) proposed an almost unbiased ridge estimator using Jackknife method that required transformation of the regression parameters. This article shows that the same method can be used to derive the Jackknifed ridge estimator of the original (untransformed) parameter without transformation. This method also leads in deriving easily the second-order Jackknifed ridge that may reduce the bias further. We further investigate the performance of these estimators along with a recent method by Batah et al. (2008 Batah, F. S.M., Ramanathan, T.V., Gore, S.D. (2008). The efficiency of modified Jack-knife and ridge type regression estimators: a comparison. Surv. Math. Applic. 3:111122. [Google Scholar]) called modified Jackknifed ridge theoretically as well as numerically.     

Measuring Usage: A Comprehensive Analysis of a Social Work Journal Collection

Abstract

This study examines what can be learned about a library’s electronic social work journal collection from usage statistics, survey data, faculty publications, and an examination of open access (OA) availability. A collections analysis was completed using data from two sources: a custom report by 1Science and results of a faculty survey on top journals for teaching. After creating a list of journals important to social work, top journals were identified by article downloads, faculty-authored publications, and references to faculty-authored papers. A publications analysis using faculty websites and author searches in Web of Science was also completed, to provide local, contextual data. SHERPA/RoMEO was used to determine the journals’ OA level and archiving policy. Library coverage for the journals was also included in the analysis. Results show that the McGill University Library has access to almost all of the journals identified as important to social work. Nearly one-third of publications authored by the McGill University School of Social Work since 2006 are OA, and more than half of the faculty in the school have at least one article published in an OA journal. While this is a good start for librarians who want to help faculty and students understand OA publishing and access, there is room for outreach in this area. While these results will aid librarians supporting faculty, students, and practitioners in the field of social work, a secondary aim of the study is to demonstrate a method that can be used by librarians undertaking similar analyses in other fields.     

国际粮食价格与能源价格的关联性——基于VECM和DCC-MGARCH模型的实证分析

使用VECM和DCC-MGARCH模型分析了国际粮食价格与能源价格间的关联性。两者的关联性主要体现在价格水平间和价格波动间的关系上。在价格水平方面,长期内,国际能源价格对粮食价格具有显著正向影响;短期内,误差修正项对短期波动偏离长期均衡的调整在总体粮食价格以及小麦价格的回归方程中作用显著。总体粮食价格对能源价格的长期影响显著,但误差修正项的短期调整作用不明显,在各类粮食价格对石油价格短期影响中,误差修正项起到显著调整作用。在价格波动方面,总体粮食价格波动与石油价格波动间存在显著正向相关关系,在具体某一类粮食中,除稻米外,小麦、玉米、大豆市场价格波动都与石油价格波动存在显著正向相关关系。     

参数与非参数回归在FDI中的比较分析

文章在对参数回归及非参数回归方法进行介绍的基础上,采用线性回归模型、引入虚拟变量的非线性回归模型以及N-W核权函数回归估计,对1983-2014年我国外商直接投资总额与GDP关系进行探讨.最后分别给出3类方法的拟合值以及MAE和MSE.从拟合效果来看,相对于线性回归模型,引入虚拟变量的非线性回归模型以及非参数回归方法更能有效地拟合FDI与GDP之间的关系,且窗宽为0.25的非参数估计效果更优.     

Inflation and the Divergence of Relative Prices: Evidence from a Cointegration Analysis

The relation between inflation and RPV plays a prominent role in explaining the costs of inflation. This study investigates whether the CPI subcategories drift apart more over a period of high inflation rates than during one of low inflation. The wider dispersion of the subcategories is reflected in an increasing number of common stochastic trends in the system of sub price indices. The results for US data as well as for cross-country comparisons indicate that the influence of inflation on the dispersion of relative prices cannot be revealed by counting cointegrating relations. Thus, the number of stochastic trends or cointegrating relations is not a reliable indicator for the distorting effect of inflation on the dispersion of relative prices.     

A Cautionary Note on the Analysis of Extreme Data with Cox Regression

This article analyzes a small censored data set to demonstrate the potential dangers of using statistical computing packages without understanding the details of statistical methods. The data, consisting of censored response times with heavy ties in one time point, were analyzed with a Cox regression model utilizing SAS PHREG and BMDP2L procedures. The p values, reported from both SAS PHREG and BMDP2L procedures, for testing the equality of two treatments vary considerably. This article illustrates that (1) the Breslow likelihood used in both BMDP2L and SAS PHREG procedures is too conservative and can have a critical effect on an extreme data set, (2) Wald's test in the SAS PHREG procedure may yield absurd results from most likelihood models, and (3) BMDP2L needs to include more than just the Breslow likelihood in future development.