查询词典 unbiased

Though the almost unbiased estimator was still a biased estimator, it has smaller bias than corresponding biased estimator.In this paper, we first study the properties of the almost unbiased generalized ridge estimator and the almost unbiased generalized Liu estimator.

但有偏估计毕竟偏离参数的真值，因此学者们又提出了几乎无偏估计的概念，虽然几乎无偏估计仍然是有偏估计，但是它比相应的有偏估计有更小的偏度。

And then some ellipses that AUGR estimator is better than the OLS estimator and AUGL estimator is better than the OLS estimator are given, respectively.Second, the definition of the almost unbiased unified biased estimator is proposed. This definition includes the familiar almost unbiased estimators in literatures, and it is the unified expression of the familiar almost unbiased estimators. Followed the biased and variance are compared of AUUB estimator and the unified biased estimator, respectively. AUUB estimator has smaller bias than UB estimator and the variance of AUUB estimator is between the variance of UB estimator and 4 times of the variance of UB estimator. Finally the properties of AUUB estimator are discussed. The conclusion is gained that there are parameters made AUUB estimator is better than OLS estimator in terms of their mean square error. The sufficient and necessary condition that AUUB estimator is admissible is given. The ellipse is given that AUUB estimator is

然后给出了几乎无偏统一有偏估计的定义，该定义包括了文献中常见的几乎无偏估计，实现了常见几乎无偏估计的统一表达式；接下来我们比较了几乎无偏统一有偏估计与统一有偏估计的偏度与方差，得出了几乎无偏统一有偏估计比统一有偏估计有较小的偏度，几乎无偏统一有偏估计的方差介于统一有偏估计的方差与统一有偏估计的方差的四倍之间的结论；最后我们对统一有偏估计的主要性质作了讨论，证明了存在参数K，S使得几乎无偏统一有偏估计在均方误差意义下优于最小二乘估计的结论，给出了几乎无偏统一有偏估计为可容许估计的充要条件，还给出了在均方误差阵意义下几乎无偏统一有偏估计优于最小二乘估计的椭球。

The adjusted R-square is still not an unbiased estimator of the population R-squared, because the ratio of two unbiased estimators is not an unbiased estimator.

调整过的R2仍不是总体R2的一个无偏估计量，因为两个无偏估计量的比例不是一个无偏估计量。

At the same time, we prove that the best linear unbiased prediction of a linear predictable variable Qy and the best linear unbiased prediction βn=(X"sV-1Xs)-1 X"sVs-1ys of regression coefficients of the finite populations βn=(X"V-1X)-1X"V-1y are admissible under matrix loss function and in the class of the linear predictions and the class that contains all predictions, and under quadratic loss function in the class of the linear predictions.

在线性预测类和一切预测类中是可容许预测，而在二次损失函数下其在线性预测类中是可容许预测。

In this paper, three robust estimators: robust best invariant quadratic unbiased estimator, robust minimum norm quadratic unbiased estimator and robust Helmert estimator have been designed. Finally, this paper states that these three classical estimators are particular cases of the RBIQUE.

导出了稳健最优不变二次无偏估计、稳健最小范数二次无偏估计、稳健Helmert估计，并说明了最优不变二次无偏估计、最小范数二次无偏估计以及Helmert估计等均是稳健最优不变二次无偏估计的特例。

When the estimator is unbiased, the numerical estimate is frequently also called unbiased.

当估计量无偏时，数字估计值也常叫做无偏的。

By means of combinatin of unscented transformation and best linear unbiased filter, a new filter named unscented transformation-best linear unbiased estimator filter was proposed to solve the above nonlinear tracking problem.

通过将无迹变换与最优线性无偏滤波器有机结合，提出一种新的BLUE滤波算法，以便解决上述非线性跟踪问题。

A software for QTL mapping—QTLMapper 2. 0 written by C/C++ language was developed. The sotftware could analyze populations of DH, RIL, F〓 and permanent F〓, and could provide unbiased estimation for all genetic main effects and/or unbiased prediction for all QE interaction effects. The software could also predict heteroses of single-cross offspring based on QTL genetic main effects and/or QE interaction effects obtained in QTL analysis of F〓 or permanent F〓 population.

用C／C++语言编写了适于分析DH群体、RIL群体、F〓群体和永久F〓群体的QTL作图软件QTLMapper 2.0，能够提供对各项遗传主效应的无偏估计和／或对QE互作效应的无偏预测，还能基于F〓群体或永久F〓群体估计的QTL遗传主效应和／或QE互作效应预测单交后代杂种优势。

Because a posteriori filter can generally get lower variance bound than a priori one, a posteriori filtering method is also given, which is unbiased to the nominal system of the interval one under consideration.

由于验后滤波算法精度比验前滤波精度高，研究了区间系统鲁棒验后滤波算法，相对区间系统的标称系统来说本文给出的鲁棒验后滤波是无偏的。

The scattering properties of particles with different shape parameters are simulated respectively in the modes of reflection and refraction. Both in the modes of reflection and refraction, the phase difference of non-spherical particle's PDA signal is the unbiased estimate of the corresponding phase difference of ideal spherical particle, and the standard deviation of angle roughness scale on particle surface impacts little on the distribution of phase difference.

本文通过物理光学的方法分析了非理想球形粒子的散射特性，利用物理光学中的稳相点理论，导出了非理想球形粒子散射光的相位表达形式，分析了非理想球形粒子的形状对PDA信号相位及相位差的影响，建立了非理想球形粒子的尺寸分布与PDA信号相位差分布之间的关系。

In the days of sailing vessels the crew were afraid they would be becalmed on the ocean.

在使用帆船的时代，船员们担心他们会因为无风而无法在海洋上航行。

As long as foreign donors pay the PA's salary bill, few expect a new intifada.

只要外国继续为巴权力机构的薪水买单，希望发动新暴动的人便寥寥无几。