
doi: 10.1214/18-ejs1394
handle: 11572/200362 , 11577/3260129
Let \( X_{1},X_{2},\ldots,X_{n} \) be a random sample with a distribution function \(F\) satisfying \[ \bar{F}\left( x\right) =x^{-\alpha} L\left(x \right), \quad x\rightarrow \infty, \] where \( \bar{F}=1-F \) and \( L\left(x \right) \) is a slowly varying function, satisfying \( L\left(tx \right) / L\left(x \right) \rightarrow 1 \) as \( x\rightarrow \infty, \) for any \( t>0\). The parameter \( \alpha>0 \) is called the tail index or the extreme value index. Using an empirical version of the real part of the characteristic function \( U\left(t \right)= E\left[\cos\left( tX\right) \right], \) i.e. \( U_{n}\left(t \right)= n^{-1} \sum_{j=1}^{n} \cos\left( tX_{j}\right)\), and evaluating \( U_{n}\left( t\right) \) at points \( t_{j}=j/\sqrt{n}, \; j=1,2,\ldots,m,\, m=\left[ n^{\delta}\right], 0<\delta< 1/2, \) the authors consider the regression equation \[ \log\left[\left( 1-U_{n}\left(t_{j} \right) \right) \right] \sim \log\left[g\left( \alpha,t_{j}\right) \right] + \alpha\log t_{j} + \varepsilon_{j}, \quad 0<\alpha\leqslant 2, \] where \( \varepsilon_{j} =\log \frac{1-U_{n}\left(t_j \right) }{1-U\left(t_j \right)}\) and \( g\left(\alpha,t \right)= \pi/2 \left[ \Gamma\left( \alpha\right) \sin\left( \alpha\pi/2 \right) \right]^{-1} L\left(1/t \right) \) if \, \( 0< \alpha<2\) and \( g\left(\alpha,t \right)= \int_{0}^{1/t} x \left[F\left(-x \right) + \bar{F}\left(x \right) \right] \, dx\) if \( \alpha =2. \) By ordinary least squares, they obtain a simple estimator \( \hat{\alpha} \) for \( \alpha \). The bias reduced version of \( \hat{\alpha} \) is also developed. The authors define a procedure to obtain a reduced bias estimator of \( \alpha \) optimized, according to generalized crossvalidation or restricted maximum likelihood, with respect to the choice of \( m, \) i.e. \(\delta\). Theoretical properties of the proposed method are derived and simulations show the performance of this estimator in a wide range of cases. An application to data sets on city sizes, facing the debated issue of distinguishing Pareto-type tails from Log-normal tails, illustrate, show the proposed method works in practice.
Applications of statistics to social sciences, Linear regression; mixed models, Statistics of extreme values; tail inference, tail index, heavy-tailed distributions, Zipf's law, 62J05, Zipf’s law, Empirical characteristic function; Heavy-tailed distributions; Regular variation; Tail index; Zipf's law; Statistics and Probability, empirical characteristic function, regular variation, Tail index, 62G32
Applications of statistics to social sciences, Linear regression; mixed models, Statistics of extreme values; tail inference, tail index, heavy-tailed distributions, Zipf's law, 62J05, Zipf’s law, Empirical characteristic function; Heavy-tailed distributions; Regular variation; Tail index; Zipf's law; Statistics and Probability, empirical characteristic function, regular variation, Tail index, 62G32
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 4 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Average | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Average | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Average |
