Uniform robustness against nonnormality of the t and f tests

The size of the two-sample t test is generally thought to be robust against nonnormal distributions if the sample sizes are large. This belief is based on central limit theory, and asymptotic expansions of the moments of the t statistic suggest that robustness may be improved for moderate sample sizes if the variance, skewness, and kurtosis of the distributions are matched, particularly if the sample sizes are also equal.

It is shown that asymptotic arguments such as these can be misleading and that, in fact, the size of the t test can be as large as unity if the distributions are allowed to be completely arbitrary. Restricting the distributions to be identical or symmetric (but otherwise arbitrary) does not guarantee that the size can be controlled either, but controlling the tail-heaviness of the distributions does. The last result is proved more generally for the k-sample F test.     

集值映象的不动点定理

关于集值映象的不动点问题,由于其在经济数学,对策论以及拟变分不等式理论、相补问题等中的重要作用,近年来引起了许多数学工作者的注意.国内外许多学者都对其进行研究,但大都在映象有凸性和闭性条件下讨论问题.这对其应用构成了很大约束.因此,许多作者致力于削弱这种约束.本文正是这一工作的继续.我们运用非线性分析中的广义KKM方法以及映象的转移开(闭)概念,在映象无凸性条件和闭性条件较弱的条件下得到了集值映象的不动点定理.     

论海滨旅游度假区季节性供求特征及应对策略--以北戴河为例

以北戴河为例,从海滨旅游度假区季节性供求特征入手,分析了突出的季节性供求矛盾对海滨旅游度假区发展的影响,提出解决海滨旅游度假区季节性供求矛盾的主要措施。     

让世界充满爱:流行歌曲中的人道主义--中国流行歌曲主题研究之三

"人道主义"是中国当代流行歌曲的一个重要主题.它的出现,主要是由于当代中国社会巨大转型的负面效应使人们产生迷惘感和隔膜感,而为了弥补现实的缺憾,给人予精神关怀,"人道主义"歌曲便应运而生.其基本内容就是表达对"人"的关爱、祝福及对爱的呼唤.其意义不仅在于表现一种现代性反思,引起"疗救的注意",以及给人温暖和鼓励,而且还扩大了流行歌曲的思想容量.     

企业财务性重组与资本性重组优劣比较

重组是我国国有企业重资本市场经营的重要方式,它对于充分利用资本市场推进国企改革起着重要的作用.主要包括:财务性重组和资本性重组.企业进行资本运营要重视风险分析与防范,充分发挥资本市场的作用,始终以提高效率为目标,以生产经营为依托,正确处理坚持主业与多元化经营的关系.     

n-D度量空间的一个不动点定理

文章定义了一个n-D度量空间，并证明在满足一个条件下的不动点定理．     

How much do OECD countries spend on social protection and how redistributive are their tax/benefit systems?

The global economic crisis has reignited interest in social policy and public spending on different types of social benefits. Public social spending‐to‐GDP ratios are often used to consider the magnitude of welfare systems in international perspective, but such comparisons alone give an incomplete picture of social effort across countries. This article looks at these different factors, before briefly considering the redistributive nature of tax/benefit systems in different member countries of the Organisation for Economic Co‐operation and Development (OECD). The article also considers trends in social spending and compares spending in the late 2000s with the early 1990s when the previous economic crisis played out. The article ends by illustrating the profound effect the recent global economic crisis had on social spending trends across OECD countries.     

Including informal economy workers in contributory social protection: Current challenges in Latin America

Owing to a favourable economic situation and to national labour market and social protection policy reforms, Latin America has witnessed significant progress in social protection coverage. Some countries, however, have seen weaker progress, with stagnant coverage levels. Several factors underlie the extension of pensions and health care coverage and the formalization of the labour market: substantial improvements in the quality of employment, more flexible eligibility criteria for contributory coverage, and the strengthening of the supervisory and regulatory roles of the State. This article first addresses the link between social protection and informality in Latin America to show the relationship between informal labour markets, the lack of social protection and the scale of unpaid contributions. Also highlighted is regional progress in extending social protection as a result of labour market formalization. Countries in the region have used various policies to encourage formalization and these have also helped to reduce wage inequalities, since formalization has had especially beneficial effects on low‐income sectors. Finally, we discuss dichotomous views on social protection financing in the region that tend to place contributory and non‐contributory financing in opposition to one another but do so in favour of the latter, tend to support proposals for limited coverage, and which do not challenge the stratification of access to social protection. The move towards a convergence of benefits is deemed essential: strategies to universalize social protection in the region should not focus exclusively on increasing resources, but must address institutional change as a crucial part of the locus of innovation.     

Social security contributions: Economic and public finance considerations

Social security contributions make up around a fourth of total tax revenue in OECD countries. However, there are concerns on the economic effects of high levies on labour. Recent studies suggest that at least a third of taxes on labour are shifted onto employers, leading to higher wage costs. We find substantial evidence in the literature that the nature of social security contributions matters. With a clear connection between contributions and rights, the employee will perceive this contribution as a price and not as a tax. As a consequence, these contributions will be less distortive in terms of labour supply, wage costs and private savings.