A new nonparametric bivariate test for two sample location problem

A strictly nonparametric bivariate test for two sample location problem is proposed. The proposed test is easy to apply and does not require the stringent condition of affine-symmetry or elliptical symmetry which is required by some of the major tests available for the same problem. The power function of the proposed test is calculated. The asymptotic distribution of the proposed test statistic is found to be normal. The power of proposed test is compared with some of the well-known tests under various distributions using Monte Carlo simulation technique. The power study shows that the proposed test statistic performs better than most of the test statistics for almost all the distributions considered here. As soon as the underlying population structure deviates from normality, the ability of the proposed test statistic to detect the smallest shift in location increases as compared to its competitors. The application of the test is shown by using a data set.     

我国流动人口的流入地分布变动趋势研究

利用1982年以来的历次全国人口普查和1%人口抽样调查的数据,本文从区域、省份、城市等层面分析了流动人口流入地分布的变动趋势。流动人口的流入地分布呈现明显的集中趋势。从区域层面来说,流动人口越来越向东部地区集中,越来越向东部和南部沿海地区集中;从省级层面来说,流动人口越来越集中流向少数省份,前5个流动人口最多的省(市、区)吸纳了全国一半的流动人口;从城市层面来说,流动人口越来越集中流向少数城市,表现出突出的极化现象;进入新世纪以来,我国正在形成一个由35个左右城市构成的沿海城市带,它们吸收了全国半数以上的流动人口。流动人口流入地分布的这种集中趋势将会继续保持下去,此乃制定与流动人口相关政策和制度的基本出发点和前提。     

Bayesian inference for the parameters of Weibull distribution under progressive Type-I interval censored data with beta-binomial removals

This article considers the problem of estimating the parameters of Weibull distribution under progressive Type-I interval censoring scheme with beta-binomial removals. Classical as well as the Bayesian procedures for the estimation of unknown model parameters have been developed. The Bayes estimators are obtained under SELF and GELF using MCMC technique. The performance of the estimators, has been discussed in terms of their MSEs. Further, expression for the expected number of total failures has been obtained. A real dataset of the survival times for patients with plasma cell myeloma is used to illustrate the suitability of the proposed methodology.     

Effects of some design factors on the distribution of similarity indices in cluster analysis

This article investigates the effects of number of clusters, cluster size, and correction for chance agreement on the distribution of two similarity indices, namely, Jaccard and Rand indices. Skewness and kurtosis are calculated for the two indices and their corrected forms then compared with those of the normal distribution. Three clustering algorithms are implemented: complete linkage, Ward, and K-means. Data were randomly generated from bivariate normal distributions with specified means and variance covariance matrices. Three-way ANOVA is performed to assess the significance of the design factors using skewness and kurtosis of the indices as responses. Test statistics for testing skewness and kurtosis and observed power are calculated. Simulation results showed that independent of the clustering algorithms or the similarity indices used, the interaction effect cluster size x number of clusters and the main effects of cluster size and number of clusters were found always significant for skewness and kurtosis. The three way interaction of cluster size x correction x number of clusters was significant for skewness of Rand and Jaccard indices using all clustering algorithms, but was not significant using Ward's method for both Rand and Jaccard indices, while significant for Jaccard only using complete linkage and K-means algorithms. The correction for chance agreement was significant for skewness and kurtosis using Rand and Jaccard indices when complete linkage method is used. Hence, such design factors must be taken into consideration when studying distribution of such indices.     

A simulation study of the Bennett test and Miller test for coefficients of variation

In the article, properties of the Bennett test and Miller test are analyzed. Assuming that the sample size is the same for each sample and considering the null hypothesis that the coefficients of variation for k populations are equal against the hypothesis that k ? 1 coefficients of variation are the same but differ from the coefficient of variation for the kth population, the empirical significance level and the power of the test are studied. Moreover, the dependence of the test statistic and the power of the test on the ratio of coefficients of variation are considered. The analyses are performed on simulated data.     

Notes on testing carry-over effects in continuous data under an incomplete block crossover design

We consider hypothesis testing and estimation of carry-over effects in continuous data under an incomplete block crossover design when comparing two experimental treatments with a placebo. We develop procedures for testing differential carry-over effects based on the weighted-least-squares (WLS) method. We apply Monte Carlo simulations to evaluate the performance of these test procedures in a variety of situations. We use the data regarding the forced expiratory volume in one second (FEV₁) readings taken from a double-blind crossover trial comparing two different doses of formoterol with a placebo to illustrate the use of test procedures proposed here.     

Exploitation aversion: When financial incentives fail to motivate agents

Studies of the principal-agent relationship find that monetary incentives work in many instances but that they can also backfire. Various mechanisms for this failure have been examined (e.g., intrinsic motivation, image concerns). We posit that an aversion to being exploited, i.e., being used instrumentally for another’s benefit, can also cause incentives to fail. Using an experiment we find that compliance is lower for exploitative principals compared to neutral ones despite using the same contracts. To corroborate our results we show that surveyed “exploitation aversion” mediates this effect. Our results have implications for the design and implementation of incentives within organizations.     

浅析中国近现代回族报刊的经济功能

由于近现代回族报刊中并没有专门的经济类报刊,因而普通报刊的经济功能被开发出来,对广大回族企业和相关经济活动起到了较好的引导和规范作用。诸如《边铎》《天山》《晨熹》等一系列回族报刊的出现,其中所描述的经济行为,所解析的经济政策等相关内容不仅提供了重要的回族经济史依据,而且还在客观上也大大缓解了当时回族聚居区的经济压力,刺激了当时回族产业的新模式的生成,并促进了当地经济和社区的繁荣,从而协调了部分政治性矛盾,进而推动了一些文化问题的解决。