Cite a risk in computing for which it is impossible or infeasible to develop a classical probability of occurence. Why?

Cite a risk in computing for which it is impossible or infeasible to develop a classical probability of
occurrence. Why?
The calculation of probability on the grounds of classical definition requires that the outcomes of an
experiment have the following probability:
a. The total possible number of outcome is finite.
b. Each outcome is equally likely
However it is to be noted that there are many real life practical or theoretical
examples/experiment/cases where the outcomes may not be finite or may not be equally likely. As
such, in those cases calculation of probability is not possible, and even if it is, it may yield a biased
or incorrect result. For example, when we talk about the salary of an individual over a period of
time, the total possible number of...