ABSTRACT
In this lecture we again consider lifetimes of individuals from the same cohort, but now our observations are more complicated and reflect realistic situations we often encounter in real life.
As we mentioned before, a cohort may consist of people of the same generation, of the same gender and of similar health. In clinical trials, for example, they often study the group of patients in more or less the same initial conditions who had undergone approximately the same treatment, say, the same type of operation.
