共查询到19条相似文献,搜索用时 62 毫秒
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高考作为人才选拔的依据,对中国高考试题所考查的难度和深度进行细致研究是必要的.本文以武小鹏的综合难度系数模型作为试题分析的总体框架,采取定量和定性相结合的方式对试题进行测评,以期为教师教学、学生学习及试题命制与优化提供启示. 相似文献
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以2013-2020年高考理科数学全国Ⅱ卷和2021-2022年高考理科数学全国乙卷为研究样本,建立了高考试题综合难度系数模型,用层次分析方法求解该模型,研究了近10年高考数学试题综合难度的演进趋势.结果表明,10年10套试题的综合难度先降后升. 相似文献
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文中利用五次整系数多项式在其范围内分解时而导出的一元二次方程判别式的整数性质,给出了五次整系数多项式的因式分解方法,从而解决了一类高次整系数多项式的因式分解问题. 相似文献
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题库建设中试题难度的修订和校准 总被引:1,自引:0,他引:1
马江山 《数学的实践与认识》2006,36(9):276-280
针对两种测量理论(CTT和IRT)统计结果之间存在的相关性,提出在题库建设中试题难度参数确定上,以IRT在试题参数测试的不变性为基础,充分利用CTT的优点,取两者之所长,将两者有机地融合,使确定的难度系数具有客观性和科学性. 相似文献
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基于IOWA算子的欧式范数综合评价方法 总被引:1,自引:0,他引:1
针对综合评价信息不完整、分布不均匀以及现实中人们总是主观性地经常“向后看”这一问题,提出了基于区间数有序加权平均算子(IOWA算子)的欧式范数综合评价方法。本文首先介绍了IOWA算子的相关知识;然后依据IOWA算子的特点,运用正态分布确定其位置加权向量,并与欧式范数结合形成加权欧式范数;最后运用一个算例验证了方法的有效性,既能充分考虑评价信息的分布情况,又使得评价更加客观准确。 相似文献
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从线性变换、线性回归和正态分布理论等方面论述了相关系数ρ被广泛应用的原因,讨论了|ρ|取最小值0和最大值1时的特性.强调了相关系数的局限性及在实际应用中应注意的问题.最后说明引进其它相关性度量指标的必要性. 相似文献
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考虑线性回归模型y=xTβ+e1其中误差e是函数系数自回归(FCA)过程.本文研究该模型未知参数的Huber-Dutter估计的渐近性质,在合理的条件下,证明了这些估计量以n-(1/2)速度渐近于正态分布. 相似文献
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We consider some nonprincipal filters of the Medvedev lattice. We prove that the filter generated by the nonzero closed degrees of difficulty is not principal and we compare this filter, with respect to inclusion, with some other filters of the lattice. All the filters considered in this paper are disjoint from the prime ideal generated by the dense degrees of difficulty. Mathematics Subject Classification: 03D30. 相似文献
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J.L. Alejandre Ana Allueva Jose Miguel Gonzalez 《Computational Optimization and Applications》2004,27(1):83-93
The degree of difficulty is an important concept in classical geometric programming theory. The dual problem is often infeasible when the degree of difficulty is negative and little has been published on this topic. In this paper, an alternative procedure is developed to find the optimal solution for the posynomial geometric programming problem with a negative degree of difficulty. First an equivalent problem was constructed with a positive degree of difficulty and the general posynomial geometric programming problem was solved using an original method previously developed by the authors. This method avoids the difficulty of non-differentiability of the dual objective function in the classical methods classified as dual. It also avoids the problem that appears when the feasible region for the dual problem is formed by an inconsistent system of linear equations. 相似文献
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彭秋艳 《数学的实践与认识》2005,35(9):216-220
讨论了一维波动方程系数反演的一种求解方法,将解进行一阶渐进展开,得到相应的反问题,将其转化为第二类Volttera型积分方程组,证明了反问题解的存在唯一性. 相似文献
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Joanna Tarasińska 《Applications of Mathematics》2003,48(1):67-72
Two estimates of the regression coefficient in bivariate normal distribution are considered: the usual one based on a sample and a new one making use of additional observations of one of the variables. They are compared with respect to variance. The same is done for two regression lines. The conclusion is that the additional observations are worth using only when the sample is very small. 相似文献
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Let n 3 and let X
1,...,X
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be positive i.i.d. random variables whose common distribution function f has a continuous p.d.f. Using earlier work of the present authors and a method due to Anosov for solving certain integro-functional equations, it is shown that the independence of the sample mean and the sample coefficient of variation is equivalent to that f is a gamma function. While the proof is of methodological interest, this conclusion can also be arrived at without any assumptions by appealing to the Laplace-Stieltjes transform, as in the Concluding Romark (Section 3). 相似文献
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基于城乡恩格尔系数、基尼系数、社会保障水平系数与城乡人口比,定义城镇、农村与合成的社会和谐系数.此定义考虑了中国的城乡二元结构的特殊国情,能够从经济学的层面较为精确地定量描述国家或地区的社会和谐状态,可用于横向和纵向比较. 相似文献