Double and group acceptance sampling plan for truncated life test based on inverse log-logistic distribution

This paper introduces a double and group acceptance sampling plans based on time truncated lifetimes when the lifetime of an item follows the inverse log-logistic (ILL) distribution with known shape parameter. The operating characteristic function and average sample number (ASN) values of the double acceptance sampling inspection plan are provided. The values of the minimum number of groups and operating characteristic function for various quality levels are obtained for a group acceptance sampling inspection plan. A comparative study between single acceptance sampling inspection plan and double acceptance sampling inspection plan is carried out in terms of sample size. One simulated example and four real-life examples are discussed to show the applicability of the proposed double and group acceptance sampling inspection plans for ILL distributed quality parameters.     

Modified maximum likelihood estimator under the Jones and Faddy's skew t-error distribution for censored regression model

It is well-known that classical Tobit estimator of the parameters of the censored regression (CR) model is inefficient in case of non-normal error terms. In this paper, we propose to use the modified maximum likelihood (MML) estimator under the Jones and Faddy''s skew t-error distribution, which covers a wide range of skew and symmetric distributions, for the CR model. The MML estimators, providing an alternative to the Tobit estimator, are explicitly expressed and they are asymptotically equivalent to the maximum likelihood estimator. A simulation study is conducted to compare the efficiencies of the MML estimators with the classical estimators such as the ordinary least squares, Tobit, censored least absolute deviations and symmetrically trimmed least squares estimators. The results of the simulation study show that the MML estimators work well among the others with respect to the root mean square error criterion for the CR model. A real life example is also provided to show the suitability of the MML methodology.     

略论19世纪70-90年代的中国木船业

在近代,随着外国侵略势力的到来,中国航运业受到了很大的冲击,中国古老的航运工具———木船受到了排挤。但由于各种原因,在19世纪70—90年代这段时间里中国木船业并没有走向灭亡,而是持续的向前发展。     

以系统化思维高质量推进江苏全面深化改革

以系统化思维高质量推进江苏全面深化改革,有利于江苏在全面深化改革中一体贯彻新发展理念、聚力培育发展新动能、统筹推进高质量发展。改革开放40年来,江苏锐意改革、大胆创新、勇立潮头。具体表现为：经济发展体制障碍不断突破,经济综合实力稳步提升;区域协调发展机制逐步构建,区域空间布局日渐优化;社会治理体制创新积极推进,社会治理水平明显提高;生态文明体制改革日益深化,“美丽江苏”建设成效初显。同时,江苏目前在发展方式转变、经济结构优化、增长动力转换等方面仍然存在不少问题和障碍。今后一段时间,江苏应站在更高起点系统谋划和推进各项改革。要着眼走在高质量发展前列,深化经济体制改革;要着眼提高保障和改善民生水平,创新社会治理格局;要着眼经济和社会事业发展全局,完善人才发展制度;要着眼人与大自然是生命共同体,推进生态文明建设。     

90后大学生思想道德建设刍议

90后大学生在思想道德方面呈现出独特性：思想观念新锐、张扬、自主、时尚;自我实现意识强,价值取向功利化;危机感强,心理承受能力有限;有较自觉的社会公德意识,能积极弘扬传统美德。这些特征的形成是受社会变革、互联网、家庭教育模式和学校思想政治教育水平等多种因素的影响。加强90后大学生思想道德建设,应以学生为中心,不断创新高校思想道德教育的方法与内容;要发挥家庭教育和社会教育的作用,形成大学生思想道德教育的合力;要加强校园网络文化建设,主动占领网络思想政治教育新阵地。     

Diagnostics of multiple group influential observations for logistic regression models

In this paper, two new multiple influential observation detection methods, GCD.GSPR and mCD*, are introduced for logistic regression. The proposed diagnostic measures are compared with the generalized difference in fits (GDFFITS) and the generalized squared difference in beta (GSDFBETA), which are multiple influential diagnostics. The simulation study is conducted with one, two and five independent variable logistic regression models. The performance of the diagnostic measures is examined for a single contaminated independent variable for each model and in the case where all the independent variables are contaminated with certain contamination rates and intensity. In addition, the performance of the diagnostic measures is compared in terms of the correct identification rate and swamping rate via a frequently referred to data set in the literature.     

On Hotelling’s T2 test in a special paired sample case

In a special paired sample case, Hotelling’s T² test based on the differences of the paired random vectors is the likelihood ratio test for testing the hypothesis that the paired random vectors have the same mean; with respect to a special group of affine linear transformations it is the uniformly most powerful invariant test for the general alternative of a difference in mean. We present an elementary straightforward proof of this result. The likelihood ratio test for testing the hypothesis that the covariance structure is of the assumed special form is derived and discussed. Applications to real data are given.     

Estimation of the smallest scale parameter of two-parameter exponential distributions

Improved point and interval estimation of the smallest scale parameter of n independent populations following two-parameter exponential distributions are studied. The model is formulated in such a way that allows for treating the estimation of the smallest scale parameter as a problem of estimating an unrestricted scale parameter in the presence of a nuisance parameter. The classes of improved point and interval estimators are enriched with Stein-type, Brewster and Zidek-type, Maruyama-type and Strawderman-type improved estimators under both quadratic and entropy losses, whereas using as a criterion the coverage probability, with Stein-type, Brewster and Zidek-type, and Maruyama-type improved intervals. The sampling framework considered incorporates important life-testing schemes such as i.i.d. sampling, type-II censoring, progressive type-II censoring, adaptive progressive type-II censoring, and record values.     

地区收入、食品价格与恩格尔系数

本文以2016年我国31个省级地区截面数据为样本,构建扩展模型考察恩格尔系数与收入、食品价格之间的关系。研究发现,恩格尔系数与地区收入存在显著的负相关性,纳入食品价格后收入对恩格尔系数的影响变得更为显著,二者关系满足恩格尔定律。恩格尔系数和以地区食品价格平价代表的食品价格之间显著正相关,若再考虑其他因素,则食品价格对恩格尔系数的影响会稍有减弱。进一步将食品区分为生活必需型食品与非生活必需型食品,测算得到的基本恩格尔系数、高阶恩格尔系数与收入之间仍呈负相关关系,但与基本恩格尔系数相比,高阶恩格尔系数与收入之间的负相关性更弱。恩格尔系数受生活必需型食品价格的影响强于非生活必需型食品价格的影响,基本恩格尔系数主要受生活必需型食品价格的影响,而高阶恩格尔系数同时受到两类食品价格的影响。     

A comparative study of confidence intervals to assess biosimilarity from analytical data

Assessment of analytical similarity of tier 1 quality attributes is based on a set of hypotheses that tests the mean difference of reference and test products against a margin adjusted for standard deviation of the reference product. Thus, proper assessment of the biosimilarity hypothesis requires statistical tests that account for the uncertainty associated with the estimations of the mean differences and the standard deviation of the reference product. Recently, a linear reformulation of the biosimilarity hypothesis has been proposed, which facilitates development and implementation of statistical tests. These statistical tests account for the uncertainty in the estimation process of all the unknown parameters. In this paper, we survey methods for constructing confidence intervals for testing the linearized reformulation of the biosimilarity hypothesis and also compare the performance of the methods. We discuss test procedures using confidence intervals to make possible comparison among recently developed methods as well as other previously developed methods that have not been applied for demonstrating analytical similarity. A computer simulation study was conducted to compare the performance of the methods based on the ability to maintain the test size and power, as well as computational complexity. We demonstrate the methods using two example applications. At the end, we make recommendations concerning the use of the methods.