Can somebody explain why in (N-2,2,0,0) two molecules are in state 1? Initially suppose that all the states have exactly

[answerhappygod]

Can somebody explain why in (N-2,2,0,0) two molecules are in
state 1?
Initially suppose that all the states have exactly the same
energy. The energies of all the configurations are then identical,
so there is no restriction on how many of the N molecules are in
each state. Now picture a large number of different instantaneous
configurations. One, for example, might be {N,0,0, …},
corresponding to every molecule being in state 0. Another might be
{N − 2,2,0,0, …}, in which two molecules are in state 1. The latter
configuration is intrinsically more likely to be found than the
former because it can be achieved in more ways: {N,0,0, …} can be
achieved in only one way, but {N − 2,2,0, …} can be achieved in N(N
− 1) different ways.