A comparison of several approximations to the power function of the likelihood ratio test in covariance structure analysis*

In this paper we compare alternative asymptotic approximations to the power of the likelihood ratio test used in covariance structure analysis for testing the fit of a model. Alternative expressions for the noncentrality parameter (ncp) lead to different approximations to the power function. It appears that for alternative covariance matrices close to the null hypothesis, the alternative ncp's lead to similar values, while for alternative covariance matrices far from H_o the different expressions for the ncp can conflict substantively. Monte Carlo evidence shows that the ncp proposed in Satorra and Saris (1985) gives the most accurate power approximations.     

Testing for abnormal security-price performance under conditions of event-period uncertainty

This paper examines an event study test procedure based on cumulative average residuals (CARs) and a boundary-crossing probability for Brownian motion. The boundary-crossing test procedure is designed to detect abnormal security-price performance under conditions of event-period uncertainty. Simulations with daily security-return data show that the boundary-crossing test is well specified under the null hypothesis and has good power properties under the alternative hypothesis of abnormal security-price performance distributed over an event period of uncertain length.     

The Multilevel Approach to Repeated Measures for Complete and Incomplete Data

Repeated measurements often are analyzed by multivariate analysis of variance (MANOVA). An alternative approach is provided by multilevel analysis, also called the hierarchical linear model (HLM), which makes use of random coefficient models. This paper is a tutorial which indicates that the HLM can be specified in many different ways, corresponding to different sets of assumptions about the covariance matrix of the repeated measurements. The possible assumptions range from the very restrictive compound symmetry model to the unrestricted multivariate model. Thus, the HLM can be used to steer a useful middle road between the two traditional methods for analyzing repeated measurements. Another important advantage of the multilevel approach to analyzing repeated measures is the fact that it can be easily used also if the data are incomplete. Thus it provides a way to achieve a fully multivariate analysis of repeated measures with incomplete data. This revised version was published online in June 2006 with corrections to the Cover Date.     

More on the correct use of omnibus tests for normality

This Monte Carlo study compares the small sample properties of some commonly used omnibus and directional tests, based on the standardized third and fourth moments, for assessing the normality of random variables: the omnibus D'Agostino K² test and the directional components, and three versions of the Jarque–Bera test.     

中国和新加坡产业内贸易与规模经济关系的协整分析

中国和新加坡产业内贸易与规模经济存在着一种长期的均衡关系,新加坡生产企业的规模经济对产业内贸易的推动作用大于中国,中国和新加坡生产企业的规模经济与产业内贸易存在单向因果关系,即规模经济促进产业内贸易.     

一纸灵魂的处方，一曲生命的悲歌——再读《红处方》

女作家毕淑敏在创作中始终关注着女性及其生存状况，《红处方》亦是如此，它被一些批评家看作是毕淑敏的女权主义开山之作，事实并非如此。在《红处方》中，强大的女性话语场背后透露出的是女性自我意识的缺失，但与之对应的是作者向读者进行着更为深切的生命体验展示及发自灵魂深处的人性拷问，为现实生活中的人们开了一纸灵魂的处方，具有深广的社会意义，对这一事实的认识是理解《红处方》的重中之重。     

密绕载流无限长螺线管管外的磁场

对于密绕载流无限长螺线管,管外的磁场是否严格为零与管外磁场和管内磁场相比是否可以忽略不计,这是两个完全不同的问题。     

基于协整分析的东北区域产业结构优化与金融支持关系研究

基于1978—2003年的统计数据,采用协整关系检验法和格兰杰(Granger)因果检验法对东北地区金融发展与产业结构优化之间的关系进行了实证检验。分析结果表明东北区域产业结构优化与金融发展之间存在长期动态均衡关系及单向因果关系,即金融发展对东北区域产业结构优化具有支持作用,从而为政府经济决策提供了政策依据。     

小学体育新课标目标统领下单元教学计划的研究

新的全日制义务教育《体育(1至6年级)课程标准,》对体育课提出了运动参与、运动技能、身体健康、心理健康和社会适应等五大领域的教学目标。文章通过实验,在对比中阐述了以新课程标准为教学目标,进行有针对性的教学设计和课堂实施,可使学生各方面的发展更符合新时期的要求的观点,并提出了单元教学计划设计的方法。     

通用ATS实现技术研究

我国武器装备通用ATS(自动测试系统)经历了从引进、仿制到自行研制的过程，但是目前通用ATS总的局面是通用ATS不通用，这种局面主要是由于国内对通用ATS实现技术缺乏统一认识造成的。基于此，本文研究了与开发通用ATS密切相关的标准／规范、硬件配置技术、接口技术、集成测试软件开发环境技术。本文的研究结果适用于所有开发通用ATS的项目。