  We propose a simple approach to predict the angular momentum I ground state
(I g.s.) probabilities of many-body systems that does not require the
diagonalization of hamiltonians with random interactions. This method is found
to be applicable to {\bf all} cases that have been discussed: even and odd
fermion systems (both in single-j and many-j shells), and boson (both sd and
sdg) systems. A simple relation for the highest angular momentum g.s.
probability is found. Furthermore, it is suggested for the first time that the
0g.s. dominance in boson systems and in even-fermion systems is given by
two-body interactions with specific features.
