Validity Analysis of Fractional Age Assumptions under Rational Interpolating Method

Abstract

Validity analysis plays important role in the study of fractional age assumptions (FAAs), which assures assumption methods be effective. This paper investigate the validity conditions of FAA under RIM introduced in Li et al. (2013). A new sufficient validity condition is obtained, which also revised one mistake in Theorem 1 of Li et al. (2013). And the necessary and sufficient condition is found, which gives the accurate range of the parameter, even a little complex in analytical form. Simulation shows a clear comparison between these two conditions. These results perfect FAA under RIM in theoretical viewpoint, and are helpful to choose appropriate parameter in actuarial practice of life insurance.