Stress-strength reliability of exponentiated Fréchet distributions based on Type-II censored data

In this paper, we consider inference of the stress-strength parameter, R, based on two independent Type-II censored samples from exponentiated Fréchet populations with different index parameters. The maximum likelihood and uniformly minimum variance unbiased estimators, exact and asymptotic confidence intervals and hypotheses testing for R are obtained. We conduct a Monte Carlo simulation study to evaluate the performance of these estimators and confidence intervals. Finally, two real data sets are analysed for illustrative purposes.     

西方金融创新理论述评

西方对金融创新首先提出理论解释的是约束引致假说和管制理论。约束引致假说认为金融创新是银行试图降低与特定资产负债表约束关联的成本。管制理论认为金融创新是管制者和被管制者之间持续的斗争。不完全市场理论认为新金融产品仅仅是金融工具特定因素组合的变化。证券设计和不完全市场模型是以一般均衡理论对金融创新过程模型化。目前尚无金融创新普遍认可和统一的理论。     

语言磨蚀新问题 ——回归假说质疑

雅克布逊回归假说是语言磨蚀领域中传统的假说,随着语言磨蚀研究进一步深化,相当多的学者认可了该假说.然而,比较失语症幼儿的语言习得和磨蚀的研究结果未能证实回归假说,对健康人群的研究同样未能证实回归假说,记忆学和心理学领域也没有理论足以支持回归假说,回归假说还有很大的验证空间,它也可能并不符合语言磨蚀规律.     

语块教学的主要心理认知理据与应用

本文探讨语块教学对提高语块意识和促进语篇生成技能的有效性,以及在外语课堂教学语境中语块教学应注意的问题,以期对课堂语言教学有所裨益。     

Why spouses depress each other: A cross‐national study to test the shared resource hypothesis in depressive symptom concordance within older adult couples

The shared resource hypothesis suggests that married couples share the same environmental resources, which shape their health concordance. This study tests its cross‐national applicability. Cross‐sectional 2012–2013 Health and Retirement Study data from China, England, Mexico, and the United States were analyzed. Heterosexual couples (age ≥60) who were married or partnered were studied (N = 20,565 pairs). Dyadic data were analyzed by multilevel models to examine the effect of self and spousal social and physical health statuses on depressive symptoms. Regression models were used to test the relationship between couples' shared resources and depressive symptom concordance. Results indicated both husbands and wives' depressive symptoms were associated with their own and spouses' social and health statuses. Most couple‐level resources were insignificant predictors for Chinese and Mexican couples' concordance, but having more social and financial resources was associated with higher concordance among British and American couples. Self‐reported health was the most consistent predictor in all countries. The shared resource hypothesis was more applicable to depressive symptom concordance within couples in the United States and England, but not in China and Mexico. Couple‐centered intervention is suggested for clinical practice, and the spousal effect should be considered in policymaking.     

Forecast mean squared error reductionin the VAR(1) process

When VAR models are used to predict future outcomes, the forecast error can be substantial. Through imposition of restrictions on the off-diagonal elements of the parameter matrix, however, the information in the process may be condensed to the marginal processes. In particular, if the cross-autocorrelations in the system are small and only a small sample is available, then such a restriction may reduce the forecast mean squared error considerably.

In this paper, we propose three different techniques to decide whether to use the restricted or unrestricted model, i.e. the full VAR(1) model or only marginal AR(1) models. In a Monte Carlo simulation study, all three proposed tests have been found to behave quite differently depending on the parameter setting. One of the proposed tests stands out, however, as the preferred one and is shown to outperform other estimators for a wide range of parameter settings.     

城市较高收入群体生育意愿偏高的现象及其理论解释——基于上海的调查

本文通过在上海市闵行区的实地调查结果,同时结合其他研究文献和社会新闻报道的资料,对发达地区较高收入者生育意愿偏高的现象及其特征进行了总结．并利用伊斯特林相对期群假说对这一现象产生的原因进行了理论分析。     

Two new estimators for the proportion of true null hypotheses in multiple test

In multiple hypothesis test, an important problem is estimating the proportion of true null hypotheses. Existing methods are mainly based on the p-values of the single tests. In this paper, we propose two new estimations for this proportion. One is a natural extension of the commonly used methods based on p-values and the other is based on a mixed distribution. Simulations show that the first method is comparable with existing methods and performs better under some cases. And the method based on a mixed distribution can get accurate estimators even if the variance of data is large or the difference between the null hypothesis and alternative hypothesis is very small.     

Combined asymmetric spatial weights matrix with application to housing prices

In this study, a combined asymmetric spatial weights matrix is proposed for capturing the unequal spatial dependence of housing prices, where the advantage of this matrix was demonstrated by a non-nested hypothesis test. To explore the heterogeneous spatial impacts of urban essential characteristics on housing prices over the eastern, central, and western regions of China, after the Lagrange multiplier and likelihood ratio tests, the spatial Durbin model using the proposed weights matrix was applied to each region. The estimation results showed that the direct impacts of college and new employment were significantly negative in the eastern region, but not significant in the central and western regions. By contrast, the direct impacts of hospitals and scenic spots were significantly positive in eastern China, but not significant in central and western China. In addition, the indirect impacts of the four variables were not significant in the three regions. These results suggest that in eastern China, the government may increase the requirements for using medical resources and close tourist attractions in a single city to cool down the skyrocketing housing prices in this area.     

Bootstrap methods for multivariate hypothesis testing

The nonparametric and parametric bootstrap methods for multivariate hypothesis testing are developed. They are used to approximate the null distribution of the test statistics proposed by Duchesne and Francq (2015 Duchesne, P., Francq, C. (2015). Multivariate hypothesis testing using generalized and {2}-inverses—with applications. Statistics 49:475–496.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]), resulting in bootstrap testing procedures. In the problem of testing for the mean vector of a multivariate distribution, the asymptotic validity of the bootstrap methods is proved. The finite sample performance of the new solutions is demonstrated by means of Monte Carlo simulation studies. They indicate that for small-sample size, the bootstrap tests provide a better finite sample properties than the asymptotic tests considered by Duchesne and Francq (2015 Duchesne, P., Francq, C. (2015). Multivariate hypothesis testing using generalized and {2}-inverses—with applications. Statistics 49:475–496.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]).