Empirical Likelihood based Confidence Regions for first order parameters of a heavy tailed distribution

Julien Worms (1) , Rym Worms (2)

1 LMV - Laboratoire de Mathématiques de Versailles
2 LAMA - Laboratoire d'Analyse et de Mathématiques Appliquées

Let $X_1, \ldots, X_n$ be some i.i.d. observations from a heavy tailed distribution $F$, i.e. such that the common distribution of the excesses over a high threshold $u_n$ can be approximated by a Generalized Pareto Distribution $G_{\gamma,\sigma_n}$ with $\gamma >0$. This work is devoted to the problem of finding confidence regions for the couple $(\gamma,\sigma_n)$ : combining the empirical likelihood methodology with estimation equations (close but not identical to the likelihood equations) introduced by J. Zhang (Australian and New Zealand J. Stat n.49(1), 2007), asymptotically valid confidence regions for $(\gamma,\sigma_n)$ are obtained and proved to perform better than Wald-type confidence regions (especially those derived from the asymptotic normality of the maximum likelihood estimators). By profiling out the scale parameter, confidence intervals for the tail index are also derived.

Mots clés: Extreme values; Generalized Pareto Distribution; Confidence regions; Empirical Likelihood; Profile empirical likelihood.; Profile empirical likelihood

Domaines: Statistiques [math.ST]; Théorie [stat.TH]

Julien Worms, Rym Worms. Empirical Likelihood based Confidence Regions for first order parameters of a heavy tailed distribution. Journal of Statistical Planning and Inference, 2011, 141 (8), pp.2769-2786. ⟨10.1016/j.jspi.2011.03.002⟩. ⟨hal-00510385⟩