Nonparametric Tests of Differences in Medians: Comparison of the Wilcoxon–Mann–Whitney and Robust Rank-Order Tests

The nonparametric Wilcoxon–Mann–Whitney test is commonly used by experimental economists for detecting differences in central tendency between two samples. This test is only theoretically appropriate under certain assumptions concerning the population distributions from which the samples are drawn, and is often used in cases where it is unclear whether these assumptions hold, and even when they clearly do not hold. Fligner and Pollicello's (1981, Journal of the American Statistical Association. 76, 162–168) robust rank-order test is a modification of the Wilcoxon–Mann–Whitney test, designed to be appropriate in more situations than Wilcoxon–Mann–Whitney. This paper uses simulations to compare the performance of the two tests under a variety of distributional assumptions. The results are mixed. The robust rank-order test tends to yield too many false positive results for medium-sized samples, but this liberalness is relatively invariant across distributional assumptions, and seems to be due to a deficiency of the normal approximation to its test statistic's distribution, rather than the test itself. The performance of the Wilcoxon–Mann–Whitney test varies hugely, depending on the distributional assumptions; in some cases, it is conservative, in others, extremely liberal. The tests have roughly similar power. Overall, the robust rank-order test performs better than Wilcoxon–Mann–Whitney, though when critical values for the robust rank-order test are not available, so that the normal approximation must be used, their relative performance depends on the underlying distributions, the sample sizes, and the level of significance used.     

高校学生理性批判思维之训练 --对经济类本科教学探讨之二:原著阅读

该文主要探讨了如何组织课堂教学方式方法接近大学教学目的：即课程内容多元性和学生批判性思考的训练。首先讨论了教学方式选择的认识论基础，再结合具体经济学课程特性，自然推演出以四个“对话”层面为特征的原著阅读的教学模式；结合笔者对多年实施的教学方法经验和效果的总结，提出了一般的结论和需要深入探讨的问题。     

Logistic违约率模型的最优样本配比与分界点研究

Logistic模型是研究违约率的主流方法之一,但目前的研究未能对最优样本配比与分界点这两个基本问题给予足够的重视.文章就此展开研究,设计了15种典型的样本配比临界点的情景,通过实证比较的方法得出1:3的样本配比与0.647的临界点比较适合我国的情况.而常用的1:1的样本配比可能并不适用.     

Time Management in the Cost Evaluation of Limited Resource Programs

Planning, implementing and evaluating an intervention program all hinge around time. A program’s actions are planned according to a forecast of the time required to achieve certain objectives, and the program’s implementation among a group of users is conditioned by its real time application. Similarly, program evaluation needs to take into consideration the time resource when analysing objectively the extent to which a program’s targets have been reached, and when conducting a cost analysis of the program. In limited resource programs, any disparity between the scheduled time and the real time available can have serious consequences, and even undermine a program’s efficacy. Time management, above all where resources are limited, is therefore the linchpin in the planning, implementation and evaluation of an intervention program. In this study we analyse the utility of PERT and CPM as basic tools for the efficient time management of limited resource programs.     

西方财务会计理论研究述评--方法论视角

财务会计研究发展演进的历史,是一部多种研究流派相互竞争,从而实现转化或者融合的进化史。笔者因循会计实践发展的脉络,从方法论的视角,对西方财务会计研究史上的主要研究流派进行回顾。     

Tourism as public culture: Horne's ideological commentary on the legerdemain of tourism

In 1992 Donald Horne–respected Australian author of The Lucky Country, The Great Museum… and The Public Culture…–produced an entertaining but enlightening work (The Intelligent Tourist) on the role and function of tourism as the modern form of secular pilgrimage. In this text, Horne perceptively explored tourism as public culture –the fashions by which governments and interested parties capture national capitals, towns, villages, museums, art galleries, ancient temples, monuments, festivals and other interpreted performances in order to project the celebrated narratives and/or the ordinary vistas of a given people, its places, and its pasts. In 1994, King reviewed Horne's examination of the makebelieve of public culture in tourism, but appears to have overlooked much of the subtle insight with which Horne examined the objectifications and inspected the commodifications of contemporary tourism, and the exteriority of various tourism presentations. Horne's powerful scrutiny of intelligence-making in the articulations of tourism warrants fuller critique; this current paper therefore recrystallises Horne's work to highlight not only the skilled legerdemain of tourism practitioners in manufacturing preferred versions of public culture, but also the rich and acerbic insight that Horne himself brings to analyses of the ideological ‘power’ of invented presentation in tourism. Thereby, the paper attempts to distill a number of large issues on evocative material symbolism that Horne insists are central to the normalisations at work today in the projected public culture of post-modern ‘nationalist’ tourism, where that representation of tourism serves as a coding machine in the interests of certain or various priviliged groups.Copyright © 1999 John Wiley & Sons, Ltd.     

九龙山致密气田压后支撑剂回流机理研究

四川九龙山气田为低孔、低渗致密砂岩气藏,储层的孔隙度和渗透率极低,但储层微裂缝较为发育。该区气井进行压裂作业后,出现了支撑剂回流的现象,支撑剂回流导致压裂支撑缝长、缝宽变小,同时也会导致导流能力下降。以单颗粒支撑剂受力分析方法为基础,研究了压裂气井支撑剂回流机理,推导了该区支撑剂发生返排的临界流速;结合改造研究区气藏的施工数据,分析了影响支撑剂回流临界流速的因素,临界流速会随着支撑剂的密度和粒径的增加而增加,而压裂液的黏度降低将会明显增大临界流速;结合工程流体力学和气藏工程原理,建立返排油嘴临界尺寸与返排临界速度的关系,通过井口控制油嘴尺寸来控制压裂液返排速度,形成了一套支撑剂回流控制技术,为现场施工控制压裂液返排提供指导。     

携号转网政策对电信运营商合谋的影响研究

电信业是一个典型的寡头垄断产业,在运营过程中,电信运营商容易达成合谋,同时电信市场较高的转移成本为电信运营商合谋提供一定的基础。本文通过构建博弈模型,研究携号转网政策对电信运营商合谋的影响效应。研究得出：实施携号转网政策,通过有效降低消费者的转移成本,使得电信运营商坚持合谋的临界贴现因子提高,电信运营商将更难坚持合谋。该政策的实施效果随转移成本降低率的提高而增强,随电信运营商产品差异性的不断扩大而减弱。因此,携号转网政策的实施将在一定程度上降低电信运营商的合谋行为。     

Business Ethics and the Idea of a Higher Education

The role of business ethics within higher education is often discussed in relation to its relevance to the business context. However, this paper is concerned with the link between business ethics and Ronald Barnett's conception of a higher education. It is argued that business ethics is the best placed subject within the business curriculum to facilitate 'critical interdisciplinarity'; to enable students to think critically about the business knowledge they already possess drawing on philosophical and sociological perspectives. The legitimacy of the business curriculum within higher education remains a contentious issue. Business ethics has a central role to play in reconciling the business curriculum with notions of a liberal higher education. It is crucial to retain the 'critical' or 'subversive' role of business ethics to counter-balance the dominant 'managerialist' perspective of the business curriculum and demonstrate that the study of business can help fulfil expectations that a higher education in business can be 'emancipatory'.     

逻辑主义关于科学与非科学的两种划界

本文简要而又全面地评述了逻辑主义(即逻辑实证主义和批判理性主义)关于科学与非科学的划界的相关思想,提出了必须区分科学与非科学的划界的两种重要涵义:第一种划界和第二种划界.首次理清了逻辑主义关于这两种划界的不同说法,而这两种划界在过去常常是混在一起的.