抽样与重抽样:一个有效的刀切法方差估计的近似

SAMPLING AND RESAMPLING: AN EFFICIENT APPROXIMATION TO JACKKNIFE VARIANCE ESTIMATORS

  • 摘要: 本文所考察的问题是如何减少一般的去d刀切法的计算。已被证明:对线性模型中的方差使用去d刀切法所得的估计量具有稳健性和其它一切渐近性质,而这些性质在传统的去1刀切法场合是不具有的。由于去d刀切方差估计量的计算量是很大的,假如从所有的 \binomnd 中随机地选出部分,组成的刀切抽样方差估计(JSVE),保持了一般去d刀切方差所具有的一切渐近性质,在小样本模拟试验也显示出一些良好性质。

     

    Abstract: The problem considered is the computation reduction for general delete-d jackknife (Wu, 8) in linear models as well as the i. i. d, case. The delete-d jackknife was proved to have a heteroscedasticity-robustness property for variance estimation in linear models (Shao and Wu, 9) and other desirable asymptotic properties which are not shared by the traditional delete-l jackknife (Shao and Wu, 11; Wu, 12). Since the delete-d jackknife is based on \binomnd recomputations of \hat\theta_\mathbfs, where n is the sample size and \hat\theta_\mathbfs is the analogue of \hat\theta based on the original sample with d observations deleted, the number of computations increases rapidly as n and d increase. Via sampling techniques, a shortcut can be achieved by evaluating m \hat\theta_\mathbfs’s randomly drawn from all the \hat\theta_\mathbfs’s. The resulting jackknife-sampling hybrid variance estimators (JSVE) are shown to possess all the asymptotic properties that the delete-d jackknife variance estimators have, as long as m=n. If m-1=o(n-1), the increase in mean squared earor by using JSVE is relatively negligible. The number of computations, however, is considerably reduced. The small sample performance and a comparison of several JSVE are studied in a simulation study.

     

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