Levene type tests for the ratio of two scales

Tests for the equality of variances are of interest in many areas such as quality control, agricultural production systems, experimental education, pharmacology, biology, as well as a preliminary to the analysis of variance, dose–response modelling or discriminant analysis. The literature is vast. Traditional non-parametric tests are due to Mood, Miller and Ansari–Bradley. A test which usually stands out in terms of power and robustness against non-normality is the W50 Brown and Forsythe [Robust tests for the equality of variances, J. Am. Stat. Assoc. 69 (1974), pp. 364–367] modification of the Levene test [Robust tests for equality of variances, in Contributions to Probability and Statistics, I. Olkin, ed., Stanford University Press, Stanford, 1960, pp. 278–292]. This paper deals with the two-sample scale problem and in particular with Levene type tests. We consider 10 Levene type tests: the W50, the M50 and L50 tests [G. Pan, On a Levene type test for equality of two variances, J. Stat. Comput. Simul. 63 (1999), pp. 59–71], the R-test [R.G. O'Brien, A general ANOVA method for robust tests of additive models for variances, J. Am. Stat. Assoc. 74 (1979), pp. 877–880], as well as the bootstrap and permutation versions of the W50, L50 and R tests. We consider also the F-test, the modified Fligner and Killeen [Distribution-free two-sample tests for scale, J. Am. Stat. Assoc. 71 (1976), pp. 210–213] test, an adaptive test due to Hall and Padmanabhan [Adaptive inference for the two-sample scale problem, Technometrics 23 (1997), pp. 351–361] and the two tests due to Shoemaker [Tests for differences in dispersion based on quantiles, Am. Stat. 49(2) (1995), pp. 179–182; Interquantile tests for dispersion in skewed distributions, Commun. Stat. Simul. Comput. 28 (1999), pp. 189–205]. The aim is to identify the effective methods for detecting scale differences. Our study is different with respect to the other ones since it is focused on resampling versions of the Levene type tests, and many tests considered here have not ever been proposed and/or compared. The computationally simplest test found robust is W50. Higher power, while preserving robustness, is achieved by considering the resampling version of Levene type tests like the permutation R-test (recommended for normal- and light-tailed distributions) and the bootstrap L50 test (recommended for heavy-tailed and skewed distributions). Among non-Levene type tests, the best one is the adaptive test due to Hall and Padmanabhan.     

Arbitrary hypotheses in linear mod fi.S with unbalanced data

The Statistical Analysis System (SAS) procedure entitled General Linear Model (GLM) includes in its output four types of estimable functions that have certain arbitrariness (represented by the letter L) in their coefficients. This paper shows how such arbitrary estimable functions are derived from the known, general expressions for hypotheses tested by traditional-style F-statisties in analysis of variance calculations that are often made for unbalanced data (i.e., data having unequal numbers of observations in their subclasses).     

Disaster‐time Economy and an Economy of Morals: A Different Economic Order from the Market Economy under Globalization*

With the experience of two severe disasters (the Hanshin Awaji Earthquake disaster of 1995 and the Great East Japan Earthquake disaster of 2011), I wish to consider “subsistence” as human life, existence equaling the basic activities of life, an essential mutual act‐like existence economy. In this paper, I pursue a positive development of “disaster‐time economics” as a research object under the larger framework of the formation of a “moral economy,” as part of a critical process. In this paper, in order that a stricken area and society may aim at the realization of a new methodology about “creative revival” for newly developing independent research involving the state of the revival fund of a wide sense is carried out. Nevertheless, there is an overall understanding of who, in what areas, and using what methodology, has conducted research in the restoration and revival process, as well as the weak points that tend to hinder the process. There is no research on the rationality and function of public finance expenditures or national sources expenditures. Therefore, in this paper, the term “disaster‐time economy” is newly prepared. From this concept, many activities of the project, service, support, self‐efforts etc. of a social and private domain are grasped from a public sphere in connection with the process of maintenance/restoration under the disaster. The feature and subject point of the process are clarified. The market economy order that is going to be produced in this process does the basic work and determines the economic order for another self‐subsistence over life.     

中国物流投入产出效率评价体系及实证检验

依据我国1996—2010年的物流业宏观统计数据，综合运用数据包络分析方法中的C2R模型和C2GS2模型，构建了物流投入与产出效率评价体系。通过实证分析发现，我国物流业1996—2000年均规模无效，投入产出没有达到最佳比例；2010年技术有效，规模有效，投入产出处于最佳比例状态，达到了规模经济；2001、2002、2008年规模效益递减；2008—2009年虽然受国际金融动荡的影响，出现技术无效状态，但从长期看规模效益递增、技术效率渐进有效。据此提出发挥规模效应、提高运输业综合效率，提高物流业从业人员综合素质、改进物流产业技术效率和大力发展铁路运输功能的建议。     

Gaia理论与绿色发展观

Gaia理论是经生态学理论和实践部分证实的学说。Gaia理论中蕴含的部分基础理论在一定程度上为绿色发展观的形成提供了理论和实践基础。Gaia理论强调生物对地球的反作用、生物与环境之间的平等关系、地球生态系统向着先进性的方向进化、生态系统的自我调节能力等基本理论。这些理论同绿色发展观又具有千丝万缕的联系，它不但能够证实绿色发展观在现阶段的可行性和必要性，同时证明了绿色发展观在现阶段具有其本身的时代性和先进性。     

细胞保护性药物对大鼠心肌再灌性心律失常的影响

心肌缺血后再灌可导致严重的心律失常 本文比较了山莨菪碱和U - 63557A(血栓素A2 合成酶抑制剂 )对再灌注后心律失常的作用 结果显示山莨菪碱可显著缩短室性心动过速(VT)和室颤 (VF)的持续时间 ,降低心律失常的发生率和动物死亡率 ;U - 63557A仅使VT和VF的持续时间明显缩短 本文提示山莨菪碱和U - 63557A可不同程度对再灌后心肌细胞起着保护作用而减轻心律失常     

大学英语演讲与辩论课程模式设置研究

从英语演讲与辩论课程的必要性和可行性入手,着重分析了其开设范围、教学目标、教学内容、教学模式以及考核手段,旨在消除学生固有的只有名人和在比赛时才要演讲的陈旧观念,使之成为真正意义上的＂public speaking＂。     

The approximation of an unbiased test with a small level for the bioequivalence problem

In the bioequivalence problem. Brown. Hwang and Munk (1997) constructed an unbiased level a test and other tests which are uniformly more powerful than the two one-sided tests procedures when a iscomparatively larger. In this paper, for a small level, an unbiased test is shown to be approxirnately constructeQ lor tnis prooiem oy using tneir Metnog. ine numerical construction is also given.     

Performance Concern,Contingent Self‐worth,and Responses to Repeated Achievement Failure in Second Graders

Individual differences in emotion, cognitions, and task choice following achievement failure are found among four‐ to seven‐year‐olds. However, neither performance deterioration during failure nor generalization after failure—aspects of the helpless pattern in 10‐year‐olds—have been reliably demonstrated in this age group. In the present study, 78 second graders worked on a series of unsolvable and solvable puzzles and then on a figure‐matching task. We assessed levels of performance concern and performance‐contingent self‐worth, and their relations to performance during and after failure. As predicted, performance concern and performance‐contingent self‐worth were independent self‐regulatory processes. Performance concern was related to strategy use during and after failure and performance‐contingent self‐worth was related to postfailure performance. These results provide empirical support for Burhans and Dweck's model of the origins of individual differences in motivation. Similarities in behaviors and mechanisms of effect for children's and adults' responses to failure are discussed.     

Estimating and Testing Nonlinear Local Dependence Between Two Time Series

ABSTRACT

The most common measure of dependence between two time series is the cross-correlation function. This measure gives a complete characterization of dependence for two linear and jointly Gaussian time series, but it often fails for nonlinear and non-Gaussian time series models, such as the ARCH-type models used in finance. The cross-correlation function is a global measure of dependence. In this article, we apply to bivariate time series the nonlinear local measure of dependence called local Gaussian correlation. It generally works well also for nonlinear models, and it can distinguish between positive and negative local dependence. We construct confidence intervals for the local Gaussian correlation and develop a test based on this measure of dependence. Asymptotic properties are derived for the parameter estimates, for the test functional and for a block bootstrap procedure. For both simulated and financial index data, we construct confidence intervals and we compare the proposed test with one based on the ordinary correlation and with one based on the Brownian distance correlation. Financial indexes are examined over a long time period and their local joint behavior, including tail behavior, is analyzed prior to, during and after the financial crisis. Supplementary material for this article is available online.