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111.
The exact distribution of a modified Behrens–Fisher statistic is derived. The distribution function is mostly elementary and is simpler than the exact distribution derived by Nel et al. Its practical use (including computationalefficiency and computational convenience) is discussed. 相似文献
112.
In this article, we assume that the distribution of the error terms is skew t in two-way analysis of variance (ANOVA). Skew t distribution is very flexible for modeling the symmetric and the skew datasets, since it reduces to the well-known normal, skew normal, and Student's t distributions. We obtain the estimators of the model parameters by using the maximum likelihood (ML) and the modified maximum likelihood (MML) methodologies. We also propose new test statistics based on these estimators for testing the equality of the treatment and the block means and also the interaction effect. The efficiencies of the ML and the MML estimators and the power values of the test statistics based on them are compared with the corresponding normal theory results via Monte Carlo simulation study. Simulation results show that the proposed methodologies are more preferable. We also show that the test statistics based on the ML estimators are more powerful than the test statistics based on the MML estimators as expected. However, power values of the test statistics based on the MML estimators are very close to the corresponding test statistics based on the ML estimators. At the end of the study, a real life example is given to show the implementation of the proposed methodologies. 相似文献
113.
Donald W. K. Andrews 《Econometrica : journal of the Econometric Society》2004,72(3):673-700
The asymptotic refinements attributable to the block bootstrap for time series are not as large as those of the nonparametric iid bootstrap or the parametric bootstrap. One reason is that the independence between the blocks in the block bootstrap sample does not mimic the dependence structure of the original sample. This is the join‐point problem. In this paper, we propose a method of solving this problem. The idea is not to alter the block bootstrap. Instead, we alter the original sample statistics to which the block bootstrap is applied. We introduce block statistics that possess join‐point features that are similar to those of the block bootstrap versions of these statistics. We refer to the application of the block bootstrap to block statistics as the block–block bootstrap. The asymptotic refinements of the block–block bootstrap are shown to be greater than those obtained with the block bootstrap and close to those obtained with the nonparametric iid bootstrap and parametric bootstrap. 相似文献
114.
“不动摇、不懈怠、不折腾”作为一个相互联系的统一整体,科学地回答了我党在领导全国人民改革发展过程中所面临的信念立场、精神状态和方法思路问题,是中华民族实现宏伟蓝图和奋斗目标的政治基础、精神要求和措施保障。推进政治体制改革必须坚持“不动摇、不懈怠、不折腾”的原则,这是由我国的基本国情、政治体制改革的社会主义性质以及国际形势的深刻变化所决定的。它要求我国的政治体制改革不能封闭僵化、停滞不前,而要解放思想,坚定改革开放的信念不动摇;不能改旗易帜、摇摆不定,而要保证人民当家作主,坚持中国特色社会主义根本政治制度;不能急躁冒进、贪多求快,而要走渐进式的政治改革之路,积极稳妥地进行;不能盲目排外、来回折腾,而要结合中国的具体实际,批判性地吸收和借鉴西方政治文明成果。 相似文献
115.
Determinanten der Sportaktivität und der Sportart im Lebenslauf 总被引:1,自引:0,他引:1
This paper investigates the impact of social class, occupational and family life-course, relocation, age, generation and gender on exercise. Longitudinal, life course-oriented analysis enables identification of the (often diverse) conditions for (re-)uptake and discontinuation of exercise. The paper takes a detailed look at different types of exercise, enabling exploration of the various motivating influences and barriers involved. The database is a retrospective representative survey of the 50 to 70 year old population of Baden-Württemberg, Germany. The results show that higher educational qualifications are associated with higher levels of exercise, whereas manual labor and – among women – childcare are associated with lower levels of exercise. With respect to the impact of education, cultural rather than economic capital seems to be the determining influence. Other factors – (un-)employment, partnership, relocation, age and cohort – tend to have more complex effects on exercise. Though being a member of the workforce reduces the likelihood of starting to exercise, it also reduces the likelihood of dropping out. Though partnership encourages the dissemination of exercise, initiation of a relationship is also associated with a higher incidence of discontinuation. Relocation prompts both initiation and discontinuation of exercise. Surprisingly, up to the over-50 age group, increasing age is associated with an increased prevalence of physical activity, especially among women. The results of analysis of social differences in terms of types of physical activity can be used in health programs to provide scientifically founded recommendations for the promotion of specific types of physical activity for lower educational groups, seniors, and other social groups whose lifestyle tends to be inactive. 相似文献
116.
本文从自然科学与人文社会科学相结合的视角 ,对地质资源旅游资源化的有关概念进行了区分和界定 ;提出了衡量地质资源旅游资源化的双重标准和相应条件 ;指出地质资源旅游资源化对地质资源价值增值 ,旅游资源与旅游环境的形成发展与保护以及旅游业可持续发展的积极作用。 相似文献
117.
118.
退休年龄与养老金支付 总被引:15,自引:0,他引:15
退休年龄由各国各地人口的平均寿命以及劳动力供求状况所决定 ,它对养老金的支付有重要影响作用。在人口老龄化日益加剧、劳动力供应日益困难的当今社会 ,不少国家和地区都做出了推迟退休年龄以维持养老基金平衡的政策选择。中国城镇职工退休年龄是几十年前规定的 ,在人口平均寿命不断增长、养老保险制度日益成熟的今天 ,也存在着推迟退休年龄的社会需求和可能条件。文章通过对养老保险制度赡养率、被动率的分析 ,提出了按男女有别、分步到位的原则推迟职工退休年龄的政策建议 ,文章还就一些地区大批办理职工提前退休的做法对养老金支付造成的压力进行了分析 相似文献
119.
直接沉淀法制备纳米氢氧化镁粉体的研究 总被引:10,自引:0,他引:10
以氯化镁和氨水为原料,加入聚乙二醇(PEG)作为分散剂,利用直接沉淀法合成了纳米级、薄片状、粒度均匀且分散性好的氢氧化镁.考察了反应温度、反应时间、M gC l2浓度、NH3.H2O浓度、反应物配比对氢氧化镁颗粒粒径的影响,并采用透射电镜(TEM)、X射线衍射(XRD)对颗粒结构进行表征. 相似文献
120.
J. Carpenter 《Journal of the Royal Statistical Society. Series B, Statistical methodology》1999,61(1):159-172
In this paper we explore the theoretical and practical implications of using bootstrap test inversion to construct confidence intervals. In the presence of nuisance parameters, we show that the coverage error of such intervals is O ( n −1/2 ) which may be reduced to O ( n −1 ) if a Studentized statistic is used. We present three simulation studies and compare the performance of test inversion methods with established methods on the problem of estimating a confidence interval for the dose–response parameter in models of the Japanese atomic bomb survivors data. 相似文献