PROGRESSIVE INTERVAL CENSORING: SOME MATHEMATICAL RESULTS WITH APPLICATIONS TO INFERENCE

In this paper, we will introduce a union of two methods of collecting Type-I censored data, namely interval censoring and progressive censoring. We will call the resulting sample a progressively Type-I interval censored sample.We will discuss likelihood point and interval estimation, and simulation of such a censored sample from a random sample of units put on test whose lifetime distribution is continuous. An illustrative example will also be presented.

     

Some structural properties for the just-in-time level schedule problem

Just-in-time (JIT) is a pull concept applied mainly in repetitive manufacturing systems, and it is characterized by a scenario where only the required units are produced in the required quantities at the required times. It particularly aims at eliminating wastes associated with inventories in the system. A level schedule is desirable for a JIT assembly system, as it serves as an approximation for all forms of smoothing. The min-sum formulation of the assembly line level schedule problem is one of those that has been mainly used in the literature. Using this formulation as a base, we develop some useful structural properties for the problem. Among other things, it is shown that a level schedule would tend to be more difficult to achieve for products (models) with comparatively fewer units in the products composition structure.     

Social aspirations and choice of fertility: why can status motive reduce per-capita growth?

To examine the relationship between social aspirations, fertility choices and growth performances, we develop a R&D-based model in which individuals care about the number of children they bring up and their social status. In such an economy, we find that stronger status motives have a negative effect on growth. The reason is that individuals bring up fewer children, as children are an obstacle to the achievement of their social status. Introducing an endogenous choice of quality for children, we show that stronger status motives lead individuals to bring up fewer but higher quality children. In this case, social aspirations heighten the desire of parents to substitute the quantity for the quality of children because education of children fosters society’s productive ability, indirectly improving parents’ social status. I would like to thank Michael Bleaney, Juntip Boonprakaikawe, Trudy Owens, Kaipichit Ruengsrichaiya, two anonymous referees, and one editor of the review for their helpful comments and suggestions. I am grateful to the University of Nottingham (UK) for its support during the redaction of this paper.     

换一种视角看我国人口数量与生育政策

从公共政策视角重新审视和思考人口数量和人口政策问题,认为:人口数量多少是一个相对于经济社会发展水平的问题,简单地从人均资源占有量和人均经济水平论证人口多是问题,折射出的是“人口数量决定论”;看不到长期低生育率所蕴含的人口未来发展的不良后果,把目前人口惯性增长说成“势头强劲”,是违背人口发展规律的;仅从人口数据出发决定微观家庭生育政策,是公共政策制定中典型的见数不见人的“技术主义”倾向,不符合现代社会公共政策制定的理念与程序;当市场经济体制和民主法治国家被确定为发展目标之后,公民生育权利就是不容忽视的问题,那种为国家利益牺牲个人和家庭利益的说辞丧失了逻辑的合理性.     

论社会保障支出水平适度性的分析方法

对不同的国家和地区的社会保障水平适度性的衡量应从其实际经济发展水平和劳动要素分配比率出发,将社会保障水平的总量指标和结构指标结合使用,会更加合理的透视某经济体在社会保障支出和使用方面的问题。     

Exact Interval Estimation for the Scale Family Under General Progressive Type-II Censoring

In this article, we consider a general progressively Type-II censored life test where the lifetime distribution of each test unit belongs to the scale family. We derive an exact confidence interval for the scale parameter. Using Monte Carlo simulation method, we assess the expected lower and upper limits of the proposed confidence interval for the exponential distribution. Finally, we present a numerical example to illustrate the proposed procedure.     

Distribution of the Number of Observations Greater Than the ith Dependent Progressively Type-II Censored Order Statistic and Its Use in Goodness-of-fit Testing

In a life-testing problem, it may be of interest to investigate the number of observations close to but greater than the median, minimum, or more generally, the ith progressively Type-II censored order statistic (PCOS-II). In this paper, we derive the probability mass and distribution functions of the number of observations greater than the ith PCOS-II for a system with identical components for the cases of independent as well as dependent components. The type of dependence considered among the component lifetimes is through an Archimedean copula. We also provide a goodness-of-fit method for determining the best copula model for a given PCOS-II. Finally, an example is provided to illustrate the results developed here.     

Significance levels for use in the analysis of combination drug trials

Proof of efficacy of fixed combination drugs under current guidelines requires that the combination be statistically significantly superior to each component and that, to insure model validity, each component be statistically significantly superior to a placebo. Simulations indicate that if each of these four tests is performed at a significance level of 0,05 then the actual test of effectiveness of the fixed combination drug is done at a significance level that can be as small as 0.0001. This would seem to be excessively conservative. Further simulations indicate that significance levels of approximately 0,10 to 0.20 should be employed for all tests except in unusual circumstances.     

Point and Interval Estimation for Bivariate Normal Distribution Based on Progressively Type-II Censored Data

ABSTRACT

The maximum likelihood estimates (MLEs) of parameters of a bivariate normal distribution are derived based on progressively Type-II censored data. The asymptotic variances and covariances of the MLEs are derived from the Fisher information matrix. Using the asymptotic normality of MLEs and the asymptotic variances and covariances derived from the Fisher information matrix, interval estimation of the parameters is discussed and the probability coverages of the 90% and 95% confidence intervals for all the parameters are then evaluated by means of Monte Carlo simulations. To improve the probability coverages of the confidence intervals, especially for the correlation coefficient, sample-based Monte Carlo percentage points are determined and the probability coverages of the 90% and 95% confidence intervals obtained using these percentage points are evaluated and shown to be quite satisfactory. Finally, an illustrative example is presented.     

鼓励生育政策能否提高生育率? ——基于生育成本缺口递增的视角

中国总和生育率的下降引发调整生育政策的讨论,但鲜有对鼓励生育政策的效果评估与理论解释.通过马斯洛需求层次理论构建生育成本缺口递增假说,并基于世界人口政策数据库与OECD家庭数据库对基于转移支付的鼓励生育政策进行了效果评估,得出如下结论:第一,生育成本是一种动态结构,需求跃迁导致生育成本缺口增速快于收入增速,进而决定鼓励...