Comparing diagnostic tests: test of hypothesis for likelihood ratios

Likelihood ratios (LRs) are used to characterize the efficiency of diagnostic tests. In this paper, we use the classical weighted least squares (CWLS) test procedure, which was originally used for testing the homogeneity of relative risks, for comparing the LRs of two or more binary diagnostic tests. We compare the performance of this method with the relative diagnostic likelihood ratio (rDLR) method and the diagnostic likelihood ratio regression (DLRReg) approach in terms of size and power, and we observe that the performances of CWLS and rDLR are the same when used to compare two diagnostic tests, while DLRReg method has higher type I error rates and powers. We also examine the performances of the CWLS and DLRReg methods for comparing three diagnostic tests in various sample size and prevalence combinations. On the basis of Monte Carlo simulations, we conclude that all of the tests are generally conservative and have low power, especially in settings of small sample size and low prevalence.     

Response‐adaptive designs for binary responses: How to offer patient benefit while being robust to time trends?

Response‐adaptive randomisation (RAR) can considerably improve the chances of a successful treatment outcome for patients in a clinical trial by skewing the allocation probability towards better performing treatments as data accumulates. There is considerable interest in using RAR designs in drug development for rare diseases, where traditional designs are not either feasible or ethically questionable. In this paper, we discuss and address a major criticism levelled at RAR: namely, type I error inflation due to an unknown time trend over the course of the trial. The most common cause of this phenomenon is changes in the characteristics of recruited patients—referred to as patient drift. This is a realistic concern for clinical trials in rare diseases due to their lengthly accrual rate. We compute the type I error inflation as a function of the time trend magnitude to determine in which contexts the problem is most exacerbated. We then assess the ability of different correction methods to preserve type I error in these contexts and their performance in terms of other operating characteristics, including patient benefit and power. We make recommendations as to which correction methods are most suitable in the rare disease context for several RAR rules, differentiating between the 2‐armed and the multi‐armed case. We further propose a RAR design for multi‐armed clinical trials, which is computationally efficient and robust to several time trends considered.     

Strong law of large numbers and complete convergence for non-identically distributed WOD random variables

In this paper, we establish the strong law of large numbers and complete convergence for non-identically distributed WOD random variables. We derive some new inequalities of Fuk–Nagaev type for the sums of non-identically distributed WD random variables. All these results further extend and refine previous ones.     

现代社会隐私权和知情权的边界

现代社会是权利的社会,也是权利冲突频发的社会。权利之间的冲突缘起于法律规则的模糊性、权利的滥用和权利的交互性。其实质是一种客观存在的事实而非理论预设和逻辑分析的结果。权利冲突可以大致界分为主体间的权利冲突、价值冲突、利益冲突三种类型;权利间的冲突需要借助社会控制模式(个人控制、组织控制、法律控制)并通过价值平衡方法来解决。     

Bayesian estimation and prediction for Weibull model with progressive censoring

This article presents the statistical inferences on Weibull parameters with the data that are progressively type II censored. The maximum likelihood estimators are derived. For incorporation of previous information with current data, the Bayesian approach is considered. We obtain the Bayes estimators under squared error loss with a bivariate prior distribution, and derive the credible intervals for the parameters of Weibull distribution. Also, the Bayes prediction intervals for future observations are obtained in the one- and two-sample cases. The method is shown to be practical, although a computer program is required for its implementation. A numerical example is presented for illustration and some simulation study are performed.     

All that is solid melts into work: self‐work,the ‘learning ethic’ and the work ethic

In this paper I examine the intersections between a general commitment to education and learning and the moral and ethical dimensions of the work ethic under contemporary capitalism. Drawing on Kathi Weeks' (2011) recent exploration of the work ethic in The Problem with Work, I suggest there is a relationship between the form and function of the work ethic‐ and what I term the ‘learning ethic’. I suggest that commitment to a learning ethic, to the unreserved power of learning and education‐ may reiterate a moral commitment to the personal characteristics that define the work ethic under capitalism. As a consequence, consideration of the form and function of these moral character ideals in the continuation of unequal social relations across educational and workspaces, become obfuscated by a generalized celebration of learning, education and self‐work.     

70年代国外习得顺序研究综述(二)

本文回顾了70年代句子习得顺序的相关研究,主要涉及否定句、疑问句的习得顺序的相关研究,也提及70年代提出的关于关系从句的习得顺序的三大研究假设,最后指出70年代习得顺序研究的意义和不足之处以及之后该领域的主要研究动态。     

赫哲族伦理道德初探

赫哲族的伦理道德是赫哲族人民的宝贵精神财富,它在赫哲族人民的精神生活中起着直接的规范性作用。这也表明赫哲族是一个极为讲究伦理道德的民族,其伦理道德既是中华民族传统伦理道德不可分割的组成部分,又具有自身鲜明的特点。赫哲族伦理道德在赫哲族人的生活习俗、民间文学等诸多方面都有十分具体的体现。在社会主义精神文明建设中,对赫哲族伦理道德的特点进行分析,取其精华,弃其糟粕,通过吸收和改造,使赫哲族的传统道德和社会主义道德相统一,是本文研究的主旨。     

关敬吾论日本传统故事的类型与结构

本文是日本民俗学家关敬吾先生对日本传统故事的概念界定以及对之内容、结构特点的概括,作为“他山之石”,可以给中国民俗学理论研究提供参考。     

Parameter estimation of Lindley step stress model with independent competing risk under type 1 censoring

Abstract

In literature, Lindley distribution is considered as an alternative to exponential distribution to fit lifetime data. In the present work, a Lindley step-stress model with independent causes of failure is proposed. An algorithm to generate random samples from the proposed model under type 1 censoring scheme is developed. Point and interval estimation of the model parameters is carried out using maximum likelihood method and percentile bootstrap approach. To understand the effectiveness of the resulting estimates, numerical illustration is provided based on simulated and real-life data sets.