The book concerns with the problem of estimation in heterogeneous populations in the presence of latent stochastic processes. The probabilistic properties of latent processes influence the observed features of population such as the mean value of failure time or probability to fail later then given time and so on. The same characteristics in demography are life expectancy and survival at specific age.

It is shown in the book how probabilistic methods can be applied in order to eliminate influence of latent processes on estimations of populations characteristics.

The book is oriented to the students and professionals in the flied of mathematics implementation in demography, epidemiology, health care, reliability of technical systems.