A Bayesian method of sample size determination with practical applications

Summary.  The problem motivating the paper is the determination of sample size in clinical trials under normal likelihoods and at the substantive testing stage of a financial audit where normality is not an appropriate assumption. A combination of analytical and simulation-based techniques within the Bayesian framework is proposed. The framework accommodates two different prior distributions: one is the general purpose fitting prior distribution that is used in Bayesian analysis and the other is the expert subjective prior distribution, the sampling prior which is believed to generate the parameter values which in turn generate the data. We obtain many theoretical results and one key result is that typical non-informative prior distributions lead to very small sample sizes. In contrast, a very informative prior distribution may either lead to a very small or a very large sample size depending on the location of the centre of the prior distribution and the hypothesized value of the parameter. The methods that are developed are quite general and can be applied to other sample size determination problems. Some numerical illustrations which bring out many other aspects of the optimum sample size are given.     

关于建立出版经济学的思考

建设有中国特色社会主义出版事业是理性的活动,不能没有理论的指导;出版活动同时也是经济活动,不能没有经济理论的指导。出版经济学的建立既有理论基础,又有实践基础;构建出版经济学的理论体系一定要符合社会主义市场经济的要求。出版经济学是应用经济学,在理论经济学和出版经济活动之间起着桥梁的作用;在出版经济学的研究中,如何紧密结合出版经济活动的实际,核心是要把握出版物既是商品又是精神产品这个特殊性;出版经济学的尽快成长及其对实践的指导作用的充分发挥,是出版业实现体制转轨和增长转型这两个全局性的根本转变,建设有中国特色社会主义出版事业的不可替代的重要条件。     

Linear statistics in change-point estimation and their asymptotic behaviour

ABSTRACT The limiting behaviour of Bayes procedures in the asymptotic setting of the change-point estimation problem is studied. It is shown that the distribution of the difference between the Bayes estimator and the parameter converges to the distribution of a fairly complicated random variable. A class of linear statistics is introduced, and the form of the Bayes estimator within this class is deduced. The asymptotic properties of this linear estimator are investigated in two different settings for the prior distribution.     

论明末清初杭州地区通俗小说的创作与刊刻特征

明末清初杭州的通俗小说创作与刊刻出现了新的特征:在数量上,刊刻趋于衰落,但创作出现繁荣;在质量上,创作与刊刻都注重走精品路线:书坊主注重插图精美,刊刻精准,态度严谨,评点认真、精细。小说作家注重对地域特色的自觉追求,注重对小说艺术的探索与创新;书坊主与小说家的关系密切。     

Estimation of the intercept parameter for linear regression model with uncertain non-sample prior information

This paper considers alternative estimators of the intercept parameter of the linear regression model with normal error when uncertain non-sample prior information about the value of the slope parameter is available. The maximum likelihood, restricted, preliminary test and shrinkage estimators are considered. Based on their quadratic biases and mean square errors the relative performances of the estimators are investigated. Both analytical and graphical comparisons are explored. None of the estimators is found to be uniformly dominating the others. However, if the non-sample prior information regarding the value of the slope is not too far from its true value, the shrinkage estimator of the intercept parameter dominates the rest of the estimators.     

浅谈网络应用与期刊编辑

阐述了现代网络技术在期刊编辑出版工作中的运用,认为利用网络技术,可以实现收发电子邮件、网上审稿、优化选题等,而建立期刊网站,更能发挥其网上宣传、发行、检索、编读往来、精彩文摘推荐等功能。在此基础上,提出期刊编辑必须适应编辑出版现代化的要求,熟练运用网络技术,更好地为编辑出版工作服务。     

1999-2003年双十佳社科学报实证分析

选取22种学报为对象,对其近5年的信息量、稿件来源、基金论文、合著、作者情况、时滞、关键词、参考文献、文摘率等项展开调查,并与《中国社会科学》等中外名刊进行比较。统计结果表明,双十佳学报刊均年载文量137篇,2/3的稿件来自本校,93.83%的稿件源于高校;基金论文比9.73%;合作度1.23,合著率19.31%,高职称、高学历著者占80.81%;时滞176天,篇均关键词3.5个;平均引文量7.37条,其中引用图书占72.88%,期刊占20.63%;年平均文摘率15.90%。相比较而言,双十佳学报在发文量、审稿时间、标准化著录等方面有一定优势。     

Conservative prior distributions for variance parameters in hierarchical models

Bayesian hierarchical models typically involve specifying prior distributions for one or more variance components. This is rather removed from the observed data, so specification based on expert knowledge can be difficult. While there are suggestions for “default” priors in the literature, often a conditionally conjugate inverse‐gamma specification is used, despite documented drawbacks of this choice. The authors suggest “conservative” prior distributions for variance components, which deliberately give more weight to smaller values. These are appropriate for investigators who are skeptical about the presence of variability in the second‐stage parameters (random effects) and want to particularly guard against inferring more structure than is really present. The suggested priors readily adapt to various hierarchical modelling settings, such as fitting smooth curves, modelling spatial variation and combining data from multiple sites.     

Objective Testing Procedures in Linear Models: Calibration of the p-values

Abstract.  An optimal Bayesian decision procedure for testing hypothesis in normal linear models based on intrinsic model posterior probabilities is considered. It is proven that these posterior probabilities are simple functions of the classical F -statistic, thus the evaluation of the procedure can be carried out analytically through the frequentist analysis of the posterior probability of the null. An asymptotic analysis proves that, under mild conditions on the design matrix, the procedure is consistent. For any testing hypothesis it is also seen that there is a one-to-one mapping – which we call calibration curve – between the posterior probability of the null hypothesis and the classical bi p -value. This curve adds substantial knowledge about the possible discrepancies between the Bayesian and the p -value measures of evidence for testing hypothesis. It permits a better understanding of the serious difficulties that are encountered in linear models for interpreting the p -values. A specific illustration of the variable selection problem is given.     

论科技期刊编辑出版工作中的著作权保护

以科技期刊编辑出版工作中的环节为主线,分别阐述了组稿、审稿、编辑加工、出版管理等4个环节中所涉及的有关著作权保护问题。