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121.
The mathematical problems of the – in an communication [3] described – principle for the calculation of individual thermodynamic activity coefficients of single ionic species in concentrated electrolyte solutions are specified. It is the Newtonian approximation method that makes possible the evaluation of the constants b 1,…b 4 in the concentration function (0.1) for the product of the activity coefficients. The efficiency of the method is represented by the example of the activity coefficients of pure and of – with other electrolytes – mixed solutions of NaCIO4. The individual activity coefficients of the single ionic species are evaluated for several electrolytes of the concentration range from m = 0 to m = 10 mole/kg and published at another place [3, 17, 18]. 相似文献
122.
基于公文筐测验的商业银行高层管理人员选拔研究——以商业银行高级人力资源经理岗位为例 总被引:1,自引:0,他引:1
在采用文献法、访谈法和问卷法确定了银行高级人力资源管理者胜任力模型的基础上,设计和编制了适用于商业银行人力资源经理岗位的公文筐测验。研究结果表明,公文筐测验具有较高的信度和效度,可以在商业银行高层管理人员选拔中使用,但公文筐测验必须根据具体岗位来设计题目才能保证选拔的效果。 相似文献
123.
储层非均质性研究是油田开发后期剩余油挖潜、提高采收率的关键。以河流沉积学理论为指导、以现代沉积、露头调查为依据,利用密井网条件下丰富的测井资料和储层建筑结构层次分析方法对孤岛油田馆陶组上段储层进行了研究。研究认为,孤岛油田馆陶组上段储层可划分为十个层次,并将储层精细解剖到第七层次,识别出主河道、废弃河道、决口水道等七种建筑结构要素。在储层精细对比的基础上,总结出以单一河道砂体追溯为核心建立单砂体建筑结构模型的方法,并探讨了这种地质结构模型对于油田开发挖潜的重要意义。 相似文献
124.
Helmut Finner Veronika Gontscharuk 《Journal of the Royal Statistical Society. Series B, Statistical methodology》2009,71(5):1031-1048
Summary. Estimation of the number or proportion of true null hypotheses in multiple-testing problems has become an interesting area of research. The first important work in this field was performed by Schweder and Spjøtvoll. Among others, they proposed to use plug-in estimates for the proportion of true null hypotheses in multiple-test procedures to improve the power. We investigate the problem of controlling the familywise error rate FWER when such estimators are used as plug-in estimators in single-step or step-down multiple-test procedures. First we investigate the case of independent p -values under the null hypotheses and show that a suitable choice of plug-in estimates leads to control of FWER in single-step procedures. We also investigate the power and study the asymptotic behaviour of the number of false rejections. Although step-down procedures are more difficult to handle we briefly consider a possible solution to this problem. Anyhow, plug-in step-down procedures are not recommended here. For dependent p -values we derive a condition for asymptotic control of FWER and provide some simulations with respect to FWER and power for various models and hypotheses. 相似文献
125.
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127.
卢婉红 《广州大学学报(社会科学版)》2002,1(9):77-81
本文通过对实验素材和结果的定量分析 ,探讨了可读性、题材、测试题型 (自变量 )与测试结果 (因变量 )之间的相关关系。证明了 :1.不同的题材具有不同的区分能力 ;2 .不同的题型是造成分数差异的主要因素。指出 :在被试的能力范围内 ,可读性对测试结果的影响 ,并不如国外 36项研究所表明的那么明显。含多种题材和题型的阅读理解测试 ,更能有效地反映被试在阅读理解过程中各个层次的能力。 相似文献
128.
Summary: Wald statistics in generalized linear models are asymptotically 2 distributed.
The asymptotic chi–squared law of the corresponding quadratic form shows disadvantages
with respect to the approximation of the finite–sample distribution. It is shown by means
of a comprehensive simulation study that improvements can be achieved by applying
simple finite–sample size approximations to the distribution of the quadratic form in
generalized linear models. These approximations are based on a 2 distribution with an
estimated degree of freedom that generalizes an approach by Patnaik and Pearson. Simulation studies confirm that nominal level is maintained with higher accuracy compared
to the Wald statistics. 相似文献
129.
We consider a life testing situation in which systems are subject to failure from independent competing risks. Following a failure, immediate (stage-1) procedures are used in an attempt to reach a definitive diagnosis. If these procedures fail to result in a diagnosis, this phenomenon is called masking. Stage-2 procedures, such as failure analysis or autopsy, provide definitive diagnosis for a sample of the masked cases. We show how stage-1 and stage-2 information can be combined to provide statistical inference about (a) survival functions of the individual risks, (b) the proportions of failures associated with individual risks and (c) probability, for a specified masked case, that each of the masked competing risks is responsible for the failure. Our development is based on parametric distributional assumptions and the special case for which the failure times for the competing risks have a Weibull distribution is discussed in detail. 相似文献
130.
In this paper, we propose the incremental group testing model for the gap closing problem, which assumes that we can tell the difference between the outcome of testing a subset S, and the outcome of testing S {x}. We also give improvements over currently best results in literature for some other models. 相似文献