## The Annals of Statistics

### The sample autocorrelations of heavy-tailed processes with applications to ARCH

#### Abstract

We study the sample ACVF and ACF of a general stationary sequence under a weak mixing condition and in the case that the marginal distributions are regularly varying. This includes linear and bilinear processes with regularly varying noise and ARCH processes, their squares and absolute values. We show that the distributional limits of the sample ACF can be random, provided that the variance of the marginal distribution is infinite and the process is nonlinear. This is in contrast to infinite variance linear processes. If the process has a finite second but infinite fourth moment, then the sample ACF is consistent with scaling rates that grow at a slower rate than the standard $\sqrt{n}$. Consequently, asymptotic confidence bands are wider than those constructed in the classical theory. We demonstrate the theory in full detail for an ARCH (1) process.

#### Article information

Source
Ann. Statist., Volume 26, Number 5 (1998), 2049-2080.

Dates
First available in Project Euclid: 21 June 2002

https://projecteuclid.org/euclid.aos/1024691368

Digital Object Identifier
doi:10.1214/aos/1024691368

Mathematical Reviews number (MathSciNet)
MR1673289

Zentralblatt MATH identifier
0929.62092

#### Citation

Davis, Richard A.; Mikosch, Thomas. The sample autocorrelations of heavy-tailed processes with applications to ARCH. Ann. Statist. 26 (1998), no. 5, 2049--2080. doi:10.1214/aos/1024691368. https://projecteuclid.org/euclid.aos/1024691368

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• FORT COLLINS, COLORADO 80523-1877 UNIVERSITY OF GRONINGEN E-MAIL: rdavis@stat.colostate.edu NL-9700 AV GRONINGEN THE NETHERLANDS