Group sequential x2 statistic for testing the difference of two mean vectors in clinical trials

In this study we discuss the group sequential procedures for comparing two treatments based on multivariate observations in clinical trials. Also we suppose that a response vector on each of two treatments has a multivariate normal distribution with unknown covariance matrix. Then we propose a group sequential x² statistic in order to carry out repeated significance test for hypothesis of no difference between two population mean vectors. In order to realize the group sequential test where average sample number is reduced, we propose another modified group sequential x² statistic by extension of Jennison and Turnbull ( 1991 ). After construction of repeated confidence boundaries for making the repeated significance test, we compare two group sequential procedures based on two statistics regarding the average sample number and the power of the test in the simulations.     

我国大学科技产业的发展与制度创新

大学科技企业的本质是大学衍生企业 ,其产生和发展的重要意义是制度创新 ,大学科技企业的发展必须以现代企业制度来规范校企关系 ,大学高技术公司上市是大学科技产业发展的历史性跨越。大学科技产业的发展需要建立产权激励机制     

发展高科技产业与风险投资

要发展高科技 ,实现产业化 ,使之形成国家的竞争能力 ,关键是建立一个完善的风险投资体系。文章从我国的实际出发 ,分析了限制中关村高科技发展的瓶颈 ,介绍了台湾及国外风险投资的经验 ,说明了风险资本与建立风险投资体系的关系 ,以及孵化器在风险投资中所发挥的作用     

《再别康桥》之及物性系统分析

徐志摩的代表作《再别康桥》的英译版本数量颇丰、质量各异。而对译文的评价亦是众说纷纭、缺乏客观性和权威性。本文独辟蹊径,以韩礼德的系统功能语言学为视角,对诗篇原文及英译文进行及物性对比分析,旨在一方面揭示诗歌主题,一方面审视译文质量,同时验证系统功能语言学对于诗歌解读和诗歌翻译评价的适用性和可操作性。     

How to Teach by the Unit Method

Using data from the National Center for Educational Statistics research spanning fifteen years, researchers examined the impact of national educational policy implementation on the role of social studies in elementary schools. Specifically, with the reauthorization of No Child Left Behind (NCLB) in 2007 and the continuation of federal-mandated testing of English language arts (ELA) and mathematics in grades three through five, researchers sought to understand how policy decisions to extend testing to science affected teacher decisions in regard to instructional time allocations for core subject areas of ELA, mathematics, science, and social studies in elementary schools. Results of this quantitative study offer large-scale evidence of the declining role of social studies in an era in which testing is clearly linked to subject-area importance. Findings provide an overview of the national scope of testing and the ramifications for social studies in elementary schools. Researchers conclude that curriculum standardization, accountability, and high-stakes testing have had adverse affects on social studies time allotments in comparison to tested subjects.     

左遗传环的刻画

用短正合列、相对投射模和相对内射模等同调代数中的概念及其它们的一些基本性质,给出左遗传环的几类等价条件,从而给出左遗传环一种刻画.     

三板市场:设立的必要性与发展思路

首先归纳了三板市场的特征,从历史、理论、现实三个角度论证了在我国设立三板市场的必要性,构想了我国三板市场的发展思路和发展步骤,分析了发展的障碍,进而提出了相应对策.     

高新技术企业的创业

高新技术企业的创业正在我国兴起。对高新技术企业创业的时代背景———知识经济的若干特点作出分析 ,同时参考美国硅谷发展的经验 ,结合我国实际情况探讨了高新技术企业创业的必要条件     

The Relationship between High School Sector and Educational Success: Focusing on the Social Background of Private High School Students

This study investigates the influence of high school sector on educational success in Japan. A range of previous research on disparities among high schools has revealed that high school rank (based on the academic ability of pupils, etc.) originated from the democratization of high school. However, given that the democratization of high school is supported by private high schools, high school sector may become a factor for high school ranking. The data used for the analysis are the 2005 National Survey of Social Stratification and Social Mobility (SSM) in Japan. The results indicate that students who enter private high schools have lower academic ability than students who enter public high schools. By contrast, private high school students have greater educational success than public high school students. Moreover, this study reveals that private high school students are generally from a higher social class than public high school students. Given that the use of entrance examinations for private junior high schools has been increasing since the 1990s, in the future, the effect of private schools on educational success may become stronger in not only high schools but also junior high schools. This study thus emphasizes the importance of paying greater attention to the relationship between educational success and the private and public school sectors.     

Estimation of Correlation for Continuous Semimartingales

Abstract. In this study we are concerned with inference on the correlation parameter ρ of two Brownian motions, when only high‐frequency observations from two one‐dimensional continuous Itô semimartingales, driven by these particular Brownian motions, are available. Estimators for ρ are constructed in two situations: either when both components are observed (at the same time), or when only one component is observed and the other one represents its volatility process and thus has to be estimated from the data as well. In the first case it is shown that our estimator has the same asymptotic behaviour as the standard one for i.i.d. normal observations, whereas a feasible estimator can still be defined in the second framework, but with a slower rate of convergence.