Confidence intervals,significance values,maximum likelihood estimates,etc. sharpened into Occam’s razors

Abstract

Confidence sets, p values, maximum likelihood estimates, and other results of non-Bayesian statistical methods may be adjusted to favor sampling distributions that are simple compared to others in the parametric family. The adjustments are derived from a prior likelihood function previously used to adjust posterior distributions.     

BAYESIAN SUBSET SELECTION AND MODEL AVERAGING USING A CENTRED AND DISPERSED PRIOR FOR THE ERROR VARIANCE

This article proposes a new data‐based prior distribution for the error variance in a Gaussian linear regression model, when the model is used for Bayesian variable selection and model averaging. For a given subset of variables in the model, this prior has a mode that is an unbiased estimator of the error variance but is suitably dispersed to make it uninformative relative to the marginal likelihood. The advantage of this empirical Bayes prior for the error variance is that it is centred and dispersed sensibly and avoids the arbitrary specification of hyperparameters. The performance of the new prior is compared to that of a prior proposed previously in the literature using several simulated examples and two loss functions. For each example our paper also reports results for the model that orthogonalizes the predictor variables before performing subset selection. A real example is also investigated. The empirical results suggest that for both the simulated and real data, the performance of the estimators based on the prior proposed in our article compares favourably with that of a prior used previously in the literature.     

本科会计教育存在的问题及改革方向

本科会计教育作为会计教育极为重要的一部分,其发展状况决定着管理型会计人才的培养。通过对本科会计教育现状的分析和思考,提出一系列改革本科会计教育的构想。     

价值重估的尺度──论五四人学思想及其现代意义

五四新文化运动是一场价值重估运动。五四新文化运动重估一切价值的尺度是什么？在这个问题上，中国学界一直缺乏必要的认识，因而导致了对新文化运动阐释的许多混乱。其实，五四新文化先驱者们的实践早已证明：人，是五四新文化运动的基本出发点和最终目的，也是重估一切价值的最高价值尺度。五四新文化运动的先驱者们用以比较和判断东西方文明优劣的价值标准不是别的，是个人的独立、自由和权利。这是新文化运动的基本态度，因此也决定了新文化运动的根本性质。正因为这样，新文化运动才在中国文化史上具有了划时代的意义。     

On the asymptotic normality of the L1- and L2-errors in histogram density estimation

The L₁ and L₂-errors of the histogram estimate of a density f from a sample X₁,X₂,…,Xn using a cubic partition are shown to be asymptotically normal without any unnecessary conditions imposed on the density f. The asymptotic variances are shown to depend on f only through the corresponding norm of f. From this follows the asymptotic null distribution of a goodness-of-fit test based on the total variation distance, introduced by Györfi and van der Meulen (1991). This note uses the idea of partial inversion for obtaining characteristic functions of conditional distributions, which goes back at least to Bartlett (1938).     

Bayesian analysis of elapsed times in continuous‐time Markov chains

The authors consider Bayesian analysis for continuous‐time Markov chain models based on a conditional reference prior. For such models, inference of the elapsed time between chain observations depends heavily on the rate of decay of the prior as the elapsed time increases. Moreover, improper priors on the elapsed time may lead to improper posterior distributions. In addition, an infinitesimal rate matrix also characterizes this class of models. Experts often have good prior knowledge about the parameters of this matrix. The authors show that the use of a proper prior for the rate matrix parameters together with the conditional reference prior for the elapsed time yields a proper posterior distribution. The authors also demonstrate that, when compared to analyses based on priors previously proposed in the literature, a Bayesian analysis on the elapsed time based on the conditional reference prior possesses better frequentist properties. The type of prior thus represents a better default prior choice for estimation software.     

Model diagnostics for smoothing spline ANOVA models

The author proposes some simple diagnostics for assessing the necessity of selected terms in smoothing spline ANOVA models. The elimination of practically insignificant terms generally enhances the interpretability of the estimates and sometimes may also have inferential implications. The diagnostics are derived from Kullback‐Leibler geometry and are illustrated in the settings of regression, probability density estimation, and hazard rate estimation.     

Loss functions for estimation of extrema with an application to disease mapping

It is often of interest to find the maximum or near maxima among a set of vector‐valued parameters in a statistical model; in the case of disease mapping, for example, these correspond to relative‐risk “hotspots” where public‐health intervention may be needed. The general problem is one of estimating nonlinear functions of the ensemble of relative risks, but biased estimates result if posterior means are simply substituted into these nonlinear functions. The authors obtain better estimates of extrema from a new, weighted ranks squared error loss function. The derivation of these Bayes estimators assumes a hidden‐Markov random‐field model for relative risks, and their behaviour is illustrated with real and simulated data.     

都市娱乐类传媒言说风格刍议

由于对受众的想象存在着文化低端化定势,当下都市娱乐类传媒大量采用了流行言语和时尚言说方式,形成一种夸张、油腻、生僻化、雷同的言说风格。这种言说风格通过持续而广泛的传播,正在影响着我们的语言规范,其更深的社会文化背景则是公众心态的普遍浮躁和对语言规范的解构。若不注意控制这种言语文风,将对语言体系的健康发展产生过多的噪音。     

热力系统的经济评估

上海第四制药厂在抗生素生产过程系统节能技术研究中对该厂的热能供应系统提出了３个改造方案．本文以该热力系统为例,通过对各方案的技术经济分析比较,以揭示热力系统经济评估的内在含义,并提出了用参数“净年收益”作为评估依据之一的建议．