Notes on Test Homogeneity of the Odds Ratio in Matched Pairs Under Stratified Sampling: A Monte Carlo Evaluation

Using Monte Carlo simulation, we compare the performance of five asymptotic test procedures and a randomized permutation test procedure for testing the homogeneity of odds ratio under the stratified matched-pair design. We note that the weighted-least-square test procedure is liberal, while Pearson's goodness-of-fit (PGF) test procedure with the continuity correction is conservative. We note that PGF without the continuity correction, the conditional likelihood ratio test procedure, and the randomized permutation test procedure can generally perform well with respect to Type I error. We use the data taken from a case–control study regarding the endometrial cancer incidence published elsewhere to illustrate the use of these test procedures.     

The robustness of the likelihood ratio test,the nonparametric sum rank test,and f-ratio tests when the populations are from the negative binomial family

In this study, the robustness of power and significance level of several statistical testing methods was evaluated under the assumption that the test populations were from Poisson, negative binomial, or geometric distributions. The F-ratio test, with or without appropriate transformations, was shown to be both safe and robust for all distributions examined.     

A structured framework for assessing sensitivity to missing data assumptions in longitudinal clinical trials

The objective of this research was to demonstrate a framework for drawing inference from sensitivity analyses of incomplete longitudinal clinical trial data via a re‐analysis of data from a confirmatory clinical trial in depression. A likelihood‐based approach that assumed missing at random (MAR) was the primary analysis. Robustness to departure from MAR was assessed by comparing the primary result to those from a series of analyses that employed varying missing not at random (MNAR) assumptions (selection models, pattern mixture models and shared parameter models) and to MAR methods that used inclusive models. The key sensitivity analysis used multiple imputation assuming that after dropout the trajectory of drug‐treated patients was that of placebo treated patients with a similar outcome history (placebo multiple imputation). This result was used as the worst reasonable case to define the lower limit of plausible values for the treatment contrast. The endpoint contrast from the primary analysis was ? 2.79 (p = .013). In placebo multiple imputation, the result was ? 2.17. Results from the other sensitivity analyses ranged from ? 2.21 to ? 3.87 and were symmetrically distributed around the primary result. Hence, no clear evidence of bias from missing not at random data was found. In the worst reasonable case scenario, the treatment effect was 80% of the magnitude of the primary result. Therefore, it was concluded that a treatment effect existed. The structured sensitivity framework of using a worst reasonable case result based on a controlled imputation approach with transparent and debatable assumptions supplemented a series of plausible alternative models under varying assumptions was useful in this specific situation and holds promise as a generally useful framework. Copyright © 2012 John Wiley & Sons, Ltd.     

人皆可以为尧舜:论颜元的"偏圣"观 ——兼谈明清圣人普遍化思潮

颜元承孟子性善之旨,认为"人无有不善",但他亦不得不承认人的气禀有偏正之分.在"偏亦为善"的基础上,颜元认为,气质偏驳之人能够通过后天的学习有所作为,最终成为伯夷、伊尹、柳下惠等这样的"偏圣".颜元继承了孟子、朱熹关于"偏圣"的说法,却一改孟、朱对其"虽为圣但吾不取"的态度,对"偏圣"给予正面的认可.对于气质偏驳之人如何成圣,颜元亦提供了"就其质性之近而学,近夷学夷,近惠学惠"的方案.颜元的"圣人观"受到明代以来圣人普遍化思潮的影响,他吸收了王阳明"以才力论偏圣"之思想,进而发展为"以气质论偏圣",极大地扩充了"圣人"的范畴,提供了更为多样化的成圣道路,较诸王阳明,走得更远.     

区块链技术与企业绩效:公司治理结构的调节作用

当前,我国正在全面迈进数字经济新时代.区块链技术作为数字经济最为重要的基础技术设施之一,正在加速推动新一轮产业变革和数字创新,被越来越多的企业接受和应用.区块链技术对企业绩效的作用机制是什么?针对以上问题,本研究通过倾向得分匹配方法(PSM)选取2014-2019年中国沪深A股上市公司为研究样本,以当年是否引入区块链技术作为公司治理手段为哑变量,通过计量分析研究了区块链技术应用与企业绩效之间的关系,并进一步探索了公司治理结构在区块链技术应用与企业绩效关系间的调节作用.研究发现,区块链技术应用对企业绩效有促进作用;当公司治理结构呈现较高独董比例和较高股权集中度时,区块链技术应用对企业绩效的促进作用得到加强.     

Second order tail behaviour of randomly weighted heavy-tailed sums and their maxima

Abstract

In this paper the second order asymptotics of the tail probabilities of randomly weighted sums and their maxima are established in the case that the underlying primary random variables are subexponential. No any assumption is made on the dependence structure between the random weights, but we assume these weights are bounded away from zero and infinity.     

The Optimal Allocation Combination for the One-Sided Sequential Screening Procedure Based on the Individual Misclassification Error

In this article, the expected total costs of three kinds of quality cost functions for the one-sided sequential screening procedure based on the individual misclassification error are obtained, where the expected total cost is the sum of the expected cost of inspection, the expected cost of rejection, and the expected cost of quality. The computational formulas for three kinds of expected total costs are derived when k screening variables are allocated into r stages. The optimal allocation combination is determined based on the criterion of minimum expected total cost. At last, we give one example to illustrate the selection of the optimal allocation combination for the sequential screening procedure.