Accurate modeling is essential in integer-valued real phenomena, including the distribution of entire data, zero-inflated (ZI) data, and discrete exceedances. The Poisson and Negative Binomial distributions, along with their ZI variants, are considered suitable for modeling the entire data distribution, but they fail to capture the heavy tail behavior effectively alongside the bulk of the distribution. In contrast, the discrete generalized Pareto distribution (DGPD) is preferred for high threshold exceedances, but it becomes less effective for low threshold exceedances. However, in some applications, the selection of a suitable high threshold is challenging, and the asymptotic conditions required for using DGPD are not always met. To address these limitations, extended versions of DGPD are proposed. These extensions are designed to model one of three scenarios: first, the entire distribution of the data, including both bulk and tail and bypassing the threshold selection step; second, the entire distribution along with ZI; and third, the tail of the distribution for low threshold exceedances. The proposed extensions offer improved estimates across all three scenarios compared to existing models, providing more accurate and reliable results in simulation studies and real data applications.
翻译:在整数型实际现象的精确建模中,包括整体数据分布、零膨胀数据以及离散超越值的建模至关重要。泊松分布与负二项分布及其零膨胀变体虽适用于整体数据分布的建模,但难以在描述主体分布的同时有效捕捉重尾特性。相比之下,离散广义帕累托分布虽适用于高阈值超越值的建模,但对低阈值超越值的拟合效果欠佳。然而在某些应用中,合适高阈值的选取具有挑战性,且使用离散广义帕累托分布所需的渐近条件并非总能满足。为突破这些局限,本文提出了离散广义帕累托分布的扩展版本。这些扩展设计用于以下三种场景之一:第一,直接建模包含主体与尾部的整体数据分布,规避阈值选取步骤;第二,建模包含零膨胀特性的整体分布;第三,针对低阈值超越值建模数据尾部。相较于现有模型,所提出的扩展版本在三种场景中均能提供更优的估计效果,在模拟研究与实际数据应用中获得更精确可靠的结果。