A correlation-shrinkage prior for Bayesian prediction of the two-dimensional Wishart model

Autor: T Sei, F Komaki
Rok vydání: 2022
Předmět:
Zdroj: Biometrika. 109:1173-1180
ISSN: 1464-3510
0006-3444
DOI: 10.1093/biomet/asac006
Popis: Summary A Bayesian prediction problem for the two-dimensional Wishart model is investigated within the framework of decision theory. The loss function is the Kullback–Leibler divergence. We construct a scale-invariant and permutation-invariant prior distribution that shrinks the correlation coefficient. The prior is the geometric mean of the right invariant prior with respect to permutation of the indices, and is characterized by a uniform distribution for Fisher’s $z$-transformation of the correlation coefficient. The Bayesian predictive density based on the prior is shown to be minimax.
Databáze: OpenAIRE