Restricted most powerful Bayesian tests for linear models

Uniformly most powerful Bayesian tests (UMPBTs) are a new class of Bayesian tests in which null hypotheses are rejected if their Bayes factor exceeds a specified threshold. The alternative hypotheses in UMPBTs are defined to maximize the probability that the null hypothesis is rejected. Here, we generalize the notion of UMPBTs by restricting the class of alternative hypotheses over which this maximization is performed, resulting in restricted most powerful Bayesian tests (RMPBTs). We then derive RMPBTs for linear models by restricting alternative hypotheses to g priors. For linear models, the rejection regions of RMPBTs coincide with those of usual frequentist F‐tests, provided that the evidence thresholds for the RMPBTs are appropriately matched to the size of the classical tests. This correspondence supplies default Bayes factors for many common tests of linear hypotheses. We illustrate the use of RMPBTs for ANOVA tests and t‐tests and compare their performance in numerical studies.     

Mixture of linear mixed models using multivariate t distribution

Linear mixed models are widely used when multiple correlated measurements are made on each unit of interest. In many applications, the units may form several distinct clusters, and such heterogeneity can be more appropriately modelled by a finite mixture linear mixed model. The classical estimation approach, in which both the random effects and the error parts are assumed to follow normal distribution, is sensitive to outliers, and failure to accommodate outliers may greatly jeopardize the model estimation and inference. We propose a new mixture linear mixed model using multivariate t distribution. For each mixture component, we assume the response and the random effects jointly follow a multivariate t distribution, to conveniently robustify the estimation procedure. An efficient expectation conditional maximization algorithm is developed for conducting maximum likelihood estimation. The degrees of freedom parameters of the t distributions are chosen data adaptively, for achieving flexible trade-off between estimation robustness and efficiency. Simulation studies and an application on analysing lung growth longitudinal data showcase the efficacy of the proposed approach.     

试论历史纪录片中影像修辞的意义

在历史纪录片中,影像修辞已经成为了重要议题.它在增强历史叙述的说服力,促进其成为可理解的东西,增进叙述主体与读者或者观众之间的沟通,帮助后者形成历史感方面具有重大意义.     

Bayesian comparative study on binary time series

In this paper, we consider the Bayesian analysis of binary time series with different priors, namely normal, Students' t, and Jeffreys prior, and compare the results with the frequentist methods through some simulation experiments and one real data on daily rainfall in inches at Mount Washington, NH. Among Bayesian methods, our results show that the Jeffreys prior perform better in most of the situations for both the simulation and the rainfall data. Furthermore, among weakly informative priors considered, Student's t prior with 7 degrees of freedom fits the data most adequately.     

An Optimal Semiparametric Method for Two‐group Classification

In the classical discriminant analysis, when two multivariate normal distributions with equal variance–covariance matrices are assumed for two groups, the classical linear discriminant function is optimal with respect to maximizing the standardized difference between the means of two groups. However, for a typical case‐control study, the distributional assumption for the case group often needs to be relaxed in practice. Komori et al. (Generalized t ‐statistic for two‐group classification. Biometrics 2015, 71: 404–416) proposed the generalized t ‐statistic to obtain a linear discriminant function, which allows for heterogeneity of case group. Their procedure has an optimality property in the class of consideration. We perform a further study of the problem and show that additional improvement is achievable. The approach we propose does not require a parametric distributional assumption on the case group. We further show that the new estimator is efficient, in that no further improvement is possible to construct the linear discriminant function more efficiently. We conduct simulation studies and real data examples to illustrate the finite sample performance and the gain that it produces in comparison with existing methods.     

Autorität? Führung? Macht?

The topic of education and learning currently being debated with much fervor in the public arena reflects the process of change within postmodern society and its impact on the development of children and adolescents. This discussion grapples with the issue of the authority of parents and teachers as well as their role in the context of family and school. The task of trying out new roles and agreeing on them is of pre-eminent importance, since traditional role models are no longer tenable. In doing so, the relation between hierarchy and discourse is being established anew.     

Austérité budgétaire et flexibilisation du marché du travail: une association risquée

Les auteurs évaluent les effets de l'association entre politiques d'austérité budgétaire et de réduction du coût du travail, et apportent ainsi quelque éclairage sur les débats en cours. Ils s'attaquent au problème de l'agrégation dans une perspective mondiale au moyen d'un macromodèle mettant en évidence la dynamique de la répartition. La flexibilisation réduit la part salariale et entraîne des rétroactions qui s'enchaînent dans une spirale descendante avec une contraction de l'activité, même dans les économies tirées par les exportations. Les gains initiaux de compétitivité se révèlent éphémères. Sur le long terme, les salaires sont les premiers moteurs de l'économie mondiale, qui réagit positivement aux stimuli keynésiens coordonnés.     

It don't go both ways: Limited bidirectionality in sociolinguistic perception

This article explores the sociolinguistic perception of morphosyntactic variation, using sociolinguistic priming experiments. Two experiments tested participants' perception of the connection between social status and variation in two English subject‐verb agreement constructions: there's+NP and NP+don't. Experiment 1 tested sentence perception and found that exposure to non‐standard agreement boosted the perception of non‐standard agreement, but only for there's+NP. Social status cues had no effect on sentence perception. Experiment 2 tested speaker perception and found that participants were more likely to believe that non‐standard agreement was produced by low‐status than high‐status speakers. Results suggest that, especially for heavily stigmatized variables, non‐standard sentences strongly constrain the social judgments made by speakers, yet social cues do not necessarily constrain linguistic perception. The results suggest that the perceptual relationship between linguistic and social knowledge may be one of only limited bidirectionality. Implications for sociolinguistic perception and exemplar‐theoretic accounts of sociolinguistic competence are discussed.     

社区养老机构结构功能的城乡比较研究－－对杭州地区城乡三社区的个案调查

我国的社区养老机构(老年公寓、敬老院)一直以来在社会福利养老中发挥着主要作用,对这类机构在不同社区类型——城市社区、城乡结合部社区、乡村社区中进行比较研究,能客观的反映其在当地的发展现状。本文运用结构功能的社会学分析方法,在对三个社区现状的实地调查基础上,从社区背景、结构比较、功能分析等方面入手,综合论述这类社区养老机构,并力图从中揭示问题,展望我国社区养老机构的发展前景。     

基于交易对称度的市场结构测度方法 改进与实证分析

对产业组织理论SCP分析范式中的市场结构测度方法进行了评述,针对行业集中度指标存在的不足,提出了更好的指标——交易对称度概念、定义和模型,并以天然橡胶生产消费市场为例进行实证分析,改进了市场结构测度方法,弥补了存在的不足。