共查询到18条相似文献,搜索用时 244 毫秒
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本文研究了Devroye和Wagner提出的两个核估计的有偏性,并给出这两个核估计的Parzen-Rosenblatt核估计有偏性的一个统一的证明. 相似文献
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回归系数的综合岭估计 总被引:8,自引:0,他引:8
林路 《数理统计与应用概率》1996,11(3):179-185
本文提出了回归系数的一种新的有偏估计--综合岭估计,讨论了综合岭估计的优良性,可容许怀等性质,给出了其迭代和极小均方程误差的无偏估计解,在综合估计下,岭估计和根方估计作为其特例,从而统一了岭估计和根方估计理论。 相似文献
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在线性回归问题中的病态条件下,提出了一个新的有偏估计及容许性证明.[1]中的估计实为此估计的一个特例.进一步针对两种特殊情况,给出了特殊的有偏估计及其容许性证明. 相似文献
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回归系数的stein型主成分估计 总被引:4,自引:0,他引:4
对于设计阵X呈病态的线性回归模型,本文提出了一种新的关于回归系数的有偏估计─stein型主成分估计,并在均方误差意义下,论证了在一定条件下stein型主成分估计优于主成分估计,因此也优于stein型OLS估计与OLS估计,最后,我们又对偏参数的存在性,最优性进行了讨论,并得出了一些重要结论. 相似文献
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广义比估计与广义差估计及其优良性 总被引:2,自引:1,他引:1
本文提出了一个新的估计-广义比估计,将它与通常的广义差估计作了比较,并讨论了这两种估计的优良性.最后给出了一个有意义的应用. 相似文献
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研究了半参数回归模型的参数估计问题,利用压缩估计方法给出了模型的一类有偏估计,并与最小二乘估计、岭估计、几乎无偏岭估计进行了比较.在均方误差意义下,新的压缩估计明显优于最小二乘估计.最后讨论了有偏参数选取的问题. 相似文献
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本文在α-混合严平稳过程的假设下,研究了条件概率密度核估计的偏和均方误差.在此基础上给出了核估计的渐近最优带宽,并以S&P500指数为例展示了本文的结果. 相似文献
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In this study, we derive stochastic models of population dynamics and devise a new method of estimating the models. The models allow growth and harvest to be nonlinear functions of stochastic processes and the error terms to be nonlinear and heteroskedastic. Ordinary least-squares estimates would be biased and inefficient and generalized least-squares estimates cannot be calculated. Therefore, we implement nonlinear maximum likelihood methods to find unbiased and efficient estimates of parameters. The method is applied to the population dynamics of kangaroos in South Australia. Aerial survey data of kangaroo numbers are combined with harvest, effort and rainfall data to estimate the growth and harvest functions and the variances of the stochastic processes which drive the system. Results suggest that growth and harvest should be modeled as functions of stochastic processes and that observations on kangaroo numbers are critical for estimating population dynamics. The results also indicate that the estimation method works well and is a viable alternative to ARIMA and GARCH models, particularly for small data sets. 相似文献
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In this paper, we are interested in the regularity estimates of the nonnegative viscosity super solution of the $β$−biased infinity Laplacian equation $$∆^β_∞u = 0,$$ where $β ∈ \mathbb{R}$ is a fixed constant and $∆^β_∞u := ∆^N_∞u + β|Du|,$ which arises from the random game named biased tug-of-war. By studying directly the $β$−biased infinity Laplacian equation, we construct the appropriate exponential cones as barrier functions to establish a key estimate. Based on this estimate, we obtain the Harnack inequality, Hopf boundary point lemma, Lipschitz estimate and the Liouville property etc. 相似文献
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The logarithm of the determinant of a contingency table allows evolutionary information to be recovered from data generated under very general stochastic models. The variance of the estimate of the dissimilarity between taxa is generally estimated with the help of resampling methods. We show that this technique leads to biased estimates, and we derive exact formula. Practical implications are considered. 相似文献
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In this paper, we present some new smoothing techniques to solve general nonlinear complementarity problems. Under a weaker condition than monotonicity as on the original problems, we prove convergence of our methods. We also present an error estimate under a general monotonicity condition. Some numerical tests confirm the efficiency of the proposed methods. 相似文献
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岭估计是解决多元线性回归多重共线性问题的有效方法,是有偏的压缩估计。与普通最小二乘估计相比,岭估计可以降低参数估计的均方误差,但是却增大残差平方和,拟合效果变差。本文提出一种基于泛岭估计对岭估计过度压缩的改进方法,可以改进岭估计的拟合效果,减小岭估计残差平方和的增加幅度。 相似文献
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线性回归诊断的若干问题 总被引:3,自引:0,他引:3
本文对于线性回归诊断提出了几种新的模型和方法。我们首次研究了方差加权和均值漂移的混合模型,得到了相应的诊断统计量。本文还引入了罚函数方法,并以此为工具,讨论了若干有偏估计的影响度量,最后,本文提出了基于重心的诊断统计量,对于识别异常点有较好的效果。 相似文献
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We present a multistart method for solving global satisfycing problems. The method uses data generated by linearly converging local algorithms to estimate the cost value at the local minimum to which the local search is converging. When the estimate indicates that the local search is converging to a value higher than the satisfycing value, the local search is interrupted and a new local search is initiated from a randomly generated point. When the satisfycing problem is difficult and the estimation scheme is fairly accurate, the new method is superior over a straightforward adaptation of classical multistart methods. 相似文献