两个随机变量的独立性和相关性之比较

从随机变量的独立性和相关性概念出发,运用反例和定理的形式详细探讨二者的区别和联系.     

将分段函数表示为初等函数的方法

本文给出了一种化具有多个分段点，且在各区间段上的表达式为多项式函数的分段函数为初等函数的具体方法．     

基尼系数合意值和警戒线的探讨

 近年来，很多学者对基尼系数的经验法则尤其是警戒线提出了质疑。本文首先分析了收入分配的合意类型，然后依据相对贫困、贫富差距及中等收入者的收入份额三个指标来界定合意的收入分配，最后根据合意收入分配确定基尼系数的合意值和警戒线。本文结论表明，0.3—0.4可以被认为是基尼系数的合意值,0.4作为基尼系数警戒线也是比较合理的。     

基于因果关系的教育研究方法思考

探索、检验因果关系是教育科学研究的重要目标之一,相关分析、回归分析、路径分析等常用统计方法存在许多不足。结构方程模型是针对这些不足提出来的,从统计思路上,它具有优点,但还不够完善,应引起我国教育学界的注意。     

Geometric Method and Generalized Linear Models. Two Opposite Multiparametric Approaches Illustrated on a Sample of Pituitary Adenomas

We used two statistical methods to identify prognostic factors: a log-linear model (logistic and COX regression, based on the notions of linearity and multiplicative relative risk), and the CORICO method (ICOnography of CORrelations) based on the geometric significance of the correlation coefficient. We applied the methods to two different situations (a "case-control study' and a "historical cohort'). We show that the geometric exploratory tool is particularly suited to the analysis of small samples with a large number of variables. It could save time when setting up new study protocols. In this instance, the geometric approach highlighted, without preconceived ideas, the potential role of multihormonality in the course of pituitary adenoma and the unexpected influence of the date of tumour excision on the risk attached to haemorrhage.     

Uncertainty Analysis for Computer Model Projections of Hurricane Losses

Projecting losses associated with hurricanes is a complex and difficult undertaking that is wrought with uncertainties. Hurricane Charley, which struck southwest Florida on August 13, 2004, illustrates the uncertainty of forecasting damages from these storms. Due to shifts in the track and the rapid intensification of the storm, real-time estimates grew from 2 to 3 billion dollars in losses late on August 12 to a peak of 50 billion dollars for a brief time as the storm appeared to be headed for the Tampa Bay area. The storm hit the resort areas of Charlotte Harbor near Punta Gorda and then went on to Orlando in the central part of the state, with early poststorm estimates converging on a damage estimate in the 28 to 31 billion dollars range. Comparable damage to central Florida had not been seen since Hurricane Donna in 1960. The Florida Commission on Hurricane Loss Projection Methodology (FCHLPM) has recognized the role of computer models in projecting losses from hurricanes. The FCHLPM established a professional team to perform onsite (confidential) audits of computer models developed by several different companies in the United States that seek to have their models approved for use in insurance rate filings in Florida. The team's members represent the fields of actuarial science, computer science, meteorology, statistics, and wind and structural engineering. An important part of the auditing process requires uncertainty and sensitivity analyses to be performed with the applicant's proprietary model. To influence future such analyses, an uncertainty and sensitivity analysis has been completed for loss projections arising from use of a Holland B parameter hurricane wind field model. Uncertainty analysis quantifies the expected percentage reduction in the uncertainty of wind speed and loss that is attributable to each of the input variables.     

造假、治假的非合作博奕分析

简要介绍了我国假冒伪劣产品的现状及其带来的危害。应用非合作博奕理论，通过建立博奕模型，分析了假冒伪劣产品产生的根源和治理对策，并给出了对执法打假部门相应的奖励系数和对政府领导相应的罚款系数。     

经济增长差异与农产品比较优势

随着我国加入世贸组织 ,农产品比较优势问题在国内得到普遍的关注。然而 ,由于存在经济增长差异 ,有比较优势的产品 ,在国际市场上不一定有竞争优势。因此 ,要把我国农业培植成具有国际竞争力的产业 ,就必须把现有的比较优势转化为竞争优势。     

英语成绩与焦虑特性的相关性研究

文章以南华大学外国语学院英语专业二年级 4 4名本科生为对象 ,用SPSS统计软件包分析研究了学生英语成绩及若干专业技能与焦虑特性的相关性。研究结果表明 :( 1)学生英语成绩与焦虑特性呈中度负相关 ;( 2 )在听写、听力、阅读、写作这四项单项能力方面 ,听写和听力是与焦虑特性相关性最高的两个 ,而完形填空、词汇与结构与焦虑特性不相关。     

恒流管的非稳系数和改进系数

引入非稳系数和改进系数分析了四种恒流管充电式扫描电路的非线性系数和电源利用系数 ,并提出了改进恒流管充电式扫描电路性能的具体方法 .