Distribution of the two‐sample t‐test statistic following blinded sample size re‐estimation

We consider the blinded sample size re‐estimation based on the simple one‐sample variance estimator at an interim analysis. We characterize the exact distribution of the standard two‐sample t‐test statistic at the final analysis. We describe a simulation algorithm for the evaluation of the probability of rejecting the null hypothesis at given treatment effect. We compare the blinded sample size re‐estimation method with two unblinded methods with respect to the empirical type I error, the empirical power, and the empirical distribution of the standard deviation estimator and final sample size. We characterize the type I error inflation across the range of standardized non‐inferiority margin for non‐inferiority trials, and derive the adjusted significance level to ensure type I error control for given sample size of the internal pilot study. We show that the adjusted significance level increases as the sample size of the internal pilot study increases. Copyright © 2016 John Wiley & Sons, Ltd.     

空间面板杜宾模型的Bootstrap Wald-COMFAC检验研究

将共同因子约束(COMFAC)的Wald检验问题引入到空间面板模型中,讨论空间面板杜宾模型与空间面板误差模型的识别问题。蒙特卡洛模拟表明:在有限样本下,基于渐近临界值的Wald检验有着良好的检验功效,但存在着较为严重的尺度扭曲。进一步采用残差Bootstrap方法,在不损失检验功效的前提下,能够显著地降低检验的尺度扭曲。因此,残差Bootstrap方法是更为有效的检验方法。     

简论李觏的土地思想

李觏是北宋中期重要的思想家,在李觏的整个思想体系中,经济思想占有很重要的地位。李觏非常重视土地问题,土地思想是李觏经济思想的核心。针对当时土地兼并日益激烈引起的社会危害,李觏也提出了关于土地问题的看法。他的土地思想经历了前后两个时期,前期主要从分配角度分析,主张平土均田。后期主要从生产角度批判土地兼并。李觏提出了＂平土均田＂、＂井田制＂、＂农业劳动力＂、＂尽地力、广垦辟＂、＂限田＂等抑制土地兼并,发展农业,保护农民利益的思想。     

Leadership’s Role in Process Safety: An Understanding of Behavioral Science Among Managers and Executives Is Needed

ABSTRACT

A recent prevalence of high visibility catastrophic events has garnered increased attention to process safety issues. While the use of Behavior-Based Safety interventions demonstrate a reduction in workplace injuries by targeting employee behavior, we believe that process safety requires a greater focus on the behavior of leaders (e.g., creating and executing strategy). One effective method to begin targeting leader behavior for the improvement of process safety is to teach leaders about the principles of behavior, including ways by which the science may be applied within their own organizational models.     

试点营业税改增值税对企业的影响分析

当前我国正处于加快转变经济发展方式的攻坚时期,大力发展第三产业,尤其是现代服务业,对推进经济结构调整和提高综合实力具有重要意义,按照建立健全有利于科学发展的财税制度要求,将营业税改增值税,有利于完善税制,消除重复征税,降低企业税收成本,增强企业发展能力。     

Measurement Error Correction by Exploiting Gene–Environment Independence in Family‐Based Case–Control Studies

Abstract. Family‐based case–control designs are commonly used in epidemiological studies for evaluating the role of genetic susceptibility and environmental exposure to risk factors in the etiology of rare diseases. Within this framework, it is often reasonable to assume genetic susceptibility and environmental exposure being conditionally independent of each other within families in the source population. We focus on this setting to explore the situation of measurement error affecting the assessment of the environmental exposure. We correct for measurement error through a likelihood‐based method. We exploit a conditional likelihood approach to relate the probability of disease to the genetic and the environmental risk factors. We show that this approach provides less biased and more efficient results than that based on logistic regression. Regression calibration, instead, provides severely biased estimators of the parameters. The comparison of the correction methods is performed through simulation, under common measurement error structures.     

“托物取象”与诗性言说——论古典文论对李健吾文学批评的影响

李健吾的文学批评在古典文论的影响下形成了独树一帜的批评风范.他强调直觉感悟,善于营造意象,运用比喻、象征、类比等手法传达阅读感受,形成“托物取象”的论证方法;形式自由,短小精悍,文字飘逸、饱含诗情,形成了诗性言说下的散漫文体与诗意语言风格.     

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.