  In the paper is discussed complete probabilistic description of quantum
systems with application to multiqubit quantum computations. In simplest case
it is a set of probabilities of transitions to some fixed set of states. The
probabilities in the set may be represented linearly via coefficients of
density matrix and it is very similar with description using mixed states, but
also may give some alternative view on specific properties of quantum circuits
due to possibility of direct comparison with classical statistical paradigm.
