If we accept the FUNDAMENTAL ASSUMPTION at face value,
then it is easy to calculate the probability
of finding the equilibrated system in any given
fully specified state:
if the state is not accessible
[e.g. if it takes more energy U than we have at our disposal]
then the probability is zero; if it is accessible,
then its probability is just
,
where
is the total number of accessible states.
The first step is therefore to calculate .
In general this can get difficult, but we can choose a
few simple examples to illustrate how the calculation goes.