On age composition of dynamic heterogeneous populations

Abstract.Populations of items continuously manufactured and incepted into operation are characterized by the corresponding distribution of a random age at each instant of chronological time. In this study, we consider heterogeneous populations with lifetime distributions indexed by a frailty parameter. Two approaches to defining the age composition for the described populations are described and the corresponding stochastic comparisons are considered.Keywords: Age compositionfrailtyheterogeneous populationsproduction ratestochastic comparisons2010 Mathematics Subject Classification:: 60H3 AcknowledgmentsThe authors greatly thank the reviewers for their helpful comments and advice, which have improved the presentation of this paper.Disclosure statementNo potential conflict of interest was reported by the authorsAdditional informationFundingThe work of the first author was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (Grant Number: 2019R1A6A1A11051177). The work of the first author was also supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 2023R1A2C1003238).