Abstract
We extend extreme value statistics to independent data with possibly very different distributions. In particular, we present novel asymptotic normality results for the Hill estimator, which now estimates the extreme value index of the average distribution. Due to the heterogeneity, the asymptotic variance can be substantially smaller than that in the i.i.d. case. As a special case, we consider a heterogeneous scales model where the asymptotic variance can be calculated explicitly. The primary tool for the proofs is the functional central limit theorem for a weighted tail empirical process. We also present asymptotic normality results for the extreme quantile estimator. A simulation study shows the good finite-sample behavior of our limit theorems. We also present applications to assess the tail heaviness of earthquake energies and of cross-sectional stock market losses.
Acknowledgment
We are grateful to the Editor, the Associate Editor and two referees for various thoughtful comments that greatly helped improving the article.
Citation
John H.J. Einmahl. Yi He. "Extreme value inference for heterogeneous power law data." Ann. Statist. 51 (3) 1331 - 1356, June 2023. https://doi.org/10.1214/23-AOS2294
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