ASSESSING CONGRUENCEAMONG DISTANCE MATRICES: SINGLE-MALT SCOTCH WHISKIES REVISITED

A test of congruence among distance matrices is described. It tests the hypothesis that several matrices, containing different types of variables about the same objects, are congruent with one another, so they can be used jointly in statistical analysis. Raw data tables are turned into similarity or distance matrices prior to testing; they can then be compared to data that naturally come in the form of distance matrices. The proposed test can be seen as a generalization of the Mantel test of matrix correspondence to any number of distance matrices. This paper shows that the new test has the correct rate of Type I error and good power. Power increases as the number of objects and the number of congruent data matrices increase; power is higher when the total number of matrices in the study is smaller. To illustrate the method, the proposed test is used to test the hypothesis that matrices representing different types of organoleptic variables (colour, nose, body, palate and finish) in single‐malt Scotch whiskies are congruent.     

Alternative boundaries for CUSUM tests

Alternative boundaries for the common Recursive (or Standard) CUSUM test and the OLS-based CUSUM test for structural change are suggested and their properties are examined by simulation of expectedp values. The poor power of the tests for early and late structural changes can be improved for the OLS-based version, whereas this weakness of the Recursive CUSUM test cannot be overcome by the new boundaries. Research supported by the Austrian Science Foundation (FWF) under grant SFB#010 (‘Adaptive Information Systems and Modeling in Economics and Management Science’).     

Adaptive tests of regression functions via multiscale generalized likelihood ratios

Many applications of nonparametric tests based on curve estimation involve selecting a smoothing parameter. The author proposes an adaptive test that combines several generalized likelihood ratio tests in order to get power performance nearly equal to whichever of the component tests is best. She derives the asymptotic joint distribution of the component tests and that of the proposed test under the null hypothesis. She also develops a simple method of selecting the smoothing parameters for the proposed test and presents two approximate methods for obtaining its P‐value. Finally, she evaluates the proposed test through simulations and illustrates its application to a set of real data.     

TESTING SPHERICITY UNDER A MIXTURE MODEL

The robustness of Mauchly's sphericity test criterion when sampling from a mixture of two multivariate normal distributions is studied. The distribution of the sphericity test criterion when the sample covariance matrix has a non-central Wishart density of rank one is derived in terms of Meijer's G-functions; its distribution under the mixture model is then deduced. The robustness is studied by computing actual significance levels of the test under the mixture model using the critical values under the usual normal model.     

南瓜营养液的生产技术

介绍了南瓜营养液的生产工艺和动物实验效果。     

论大学英语水平统一测试的优越性

我国现行有两套考试系统用以测试大学英语水平:大学英语46、级考试(CET-4/6)用来衡量非英语专业学生的英语水平,而英语专业48、级(TEM-4/8)考试则用来测评英语专业学生的英语水平。依据Bachman和Palmer语言测试原则,为了保证语言测试的有效性,语言测试任务应该与语言应用任务相对应,这种对应是语言测试的出发点和目的。既然如此,对于非母语的中国大学生而言,就没有必要以英语专业或非英语专业的区分用不同的测试来区分他们的英语水平。从这一点出发,完全可以将现行测试非英语专业学生CET-4/6和测试英语专业学生的TEM-4/8合二为一。问卷调查分析也表明,实行全国大学英语统一测试比分成两套考试系统的英语测试更具优越性。     

大学数学教学改革的探索与思考

文章分析了当前大学数学课程教学中存在的一些问题,结合教学实际,对大学数学教学改革的目标定位进行了探讨,总结了我校数学教学工作在教学观念、教学方法、教学模式、教学内容及教材建设等方面的一些改革措施与效果。     

加入WTO后学校德育工作的若干思考

中国加入世界贸易组织,对国内教育提出新的挑战,特别是学校的德育工作面临新形势、新挑战。因此,与时俱进地加强和改进学校德育工作势在必行。本文就此从德育的内容、教学方式及德育的评价方法等几方面提出作者的建议。     

The Robustness of Trend Stationarity: An Illustration with the Extended Nelson-Plosser Dataset

We re-evaluate Andreu and Spanos's findings in favour of trend stationarity by considering the extended Nelson-Plosser data set. This expanded (to 1988) data set includes a period of rather different behaviour compared with the original Nelson-Plosser data used by Andreou and Spanos. We find that Andreou and Spanos's models (with only minor adjustments) exhibit remarable stability over this extended period, and indicate that their conclusions are more robust than they have shown.     

企业的合约经济理论探索和统计检验

对企业本质的认识是微观经济学中的一个重要问题,其对中国的国企改革有着重要意义。本文中,我们对企业的合约本质进行了经济理论探索和统计检验,并突出关注企业的激励合约问题。