Block, Li, Savits, 2003, initial and final behaviour of failure rate functions for mixtures and systems

The initial approximation of mixture failure rate is  straight forward. For each subpopulation pdf = failure rate *Viability.  Because viability approaches 1 initially, mixture of pdf leads to mixture of failure rates.

Reference:

Initial and Final Behaviour of Failure Rate Functions for Mixtures and Systems
Author(s): Henry W. Block, Yulin Li and Thomas H. Savits Source: Journal of Applied Probability, Vol. 40, No. 3 (Sep., 2003), pp. 721-740 Published by: Applied Probability Trust

Stable URL: http://www.jstor.org/stable/3215946 .