arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2012.11026stat.MEcs.ITmath.ITphysics.data-an
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独立近似使重尾分布的参数估计成为闭式估计

Independent Approximates enable closed-form estimation of heavy-tailed distributions

Kenric P. Nelson

AI总结:

独立近似方法通过闭式估计实现重尾分布参数的高效计算,适用于学生t分布等模型。

摘要:

一种新的统计估计方法,独立近似(IAs),被定义并证明能够实现重尾分布参数的闭式估计。给定来自一维分布的独立同分布样本,IAs通过将样本分成对、三元组或nth阶分组,并保留那些近似相等的分组的中位数来形成。IAs的pdf被证明是原始密度的规范化n次幂。从这一性质,重尾分布被证明其IA对具有明确的均值,IA三元组具有有限的二阶矩,以及nth分组具有有限且明确的(n-1)阶矩。通过一个由三个方程组成的系统,可以估计广义帕累托分布和学生t分布的位置、尺度和形状(逆度自由度)。IA估计方法对于学生t分布的性能分析显示,该方法收敛于最大似然估计。IA对的均值和IA三元组的二阶矩分别确定了位置和尺度的闭式估计。对于学生t分布,原始样本的几何平均值提供了一个第三个方程来确定形状,尽管其非线性解需要迭代求解器。使用10,000个样本时,参数估计的相对偏差小于0.01,相对精度小于±0.1。统计物理应用分别在331个样本的小天体物理数据集和2×10^8个样本的标准映射模拟上进行。

英文摘要:

A new statistical estimation method, Independent Approximates (IAs), is defined and proven to enable closed-form estimation of the parameters of heavy-tailed distributions. Given independent, identically distributed samples from a one-dimensional distribution, IAs are formed by partitioning samples into pairs, triplets, or nth-order groupings and retaining the median of those groupings that are approximately equal. The pdf of the IAs is proven to be the normalized n^th power of the original density. From this property, heavy-tailed distributions are proven to have well-defined means for their IA pairs, finite second moments for their IA triplets, and a finite, well-defined (n-1)^th moment for the nth grouping. Estimation of the location, scale, and shape (inverse of degree of freedom) of the generalized Pareto and Student's t distributions are possible via a system of three equations. Performance analysis of the IA estimation methodology for the Student's t distribution demonstrates that the method converges to the maximum likelihood estimate. Closed-form estimates of the location and scale are determined from the mean of the IA pairs and the second moment of the IA triplets, respectively. For the Student's t distribution, the geometric mean of the original samples provides a third equation to determine the shape, though its nonlinear solution requires an iterative solver. With 10,000 samples the relative bias of the parameter estimates is less than 0.01 and the relative precision is less than +/- 0.1. Statistical physics applications are carried out for both a small sample (331) astrophysics dataset and a large sample (2 x 10^8) standard map simulation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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