Closed Form Estimators for the Inverse Gamma and Beta Prime Distributions

Closed form estimators for the parameters of inverse gamma and beta prime distributions have not been known. The closed form estimators proposed in Iranmanesh, Vajargah and Hasanzadeh [Mathematical Sciences, 12, 2018, 71-77] are approximations. In this note, exact closed form estimators and their asymptotic distributions are derived for the inverse gamma and beta prime distributions. The better performance of the proposed estimators over the corresponding maximum likelihood estimators is noted.