Informatics and Applications

2026, Volume 20, Issue 2, pp 74-81

ASYMPTOTIC PROPERTIES OF DIGAMMA DISTRIBUTION PARAMETER ESTIMATES CONSTRUCTED FROM A SAMPLE WITH WEAKLY DEPENDENT COMPONENTS

  • A. A. Kudryavtsev
  • O. V. Shestakov

Abstract

The paper considers the digamma distribution, special cases of which can be represented as a generalized gamma distribution and a generalized beta distribution of the second kind. The strong consistency and asymptotic normality of digamma distribution parameter estimates obtained using a modified method of moments based on sample cumulants are proved in the case of weakly dependent sample components. Estimates of three unknown parameters (the characteristic exponent, shape parameters, and scale parameters) are considered for fixed concentration parameters. Estimation of the latter is not considered due to the nontrivial nature of the inversion of polygamma functions. The formulated statements pertain to a limited set of values of the estimated parameters; however, they can be easily extended to the general case using an estimation algorithm detailed in the authors' previous cited papers. The proof of the main statement is based on a sufficient condition for weak convergence of functions of asymptotically normal vectors. The results of this paper can be used to describe a wide class of distributions arising in the description of processes modeled by distributions with nonnegative, unbounded support.

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