This was one of my problems too, but watch how sensible it
sounds when translated into the scheduling example I gave:
"No matter what prior probability we put on Q, the probability
that I will be assigned to teach class R would lie
between 0.8 and 0.9.
Still, the probability that I WILL BE FORCED to teach
class R, for lack of an alternative consistent
assignment, is 0.72."
Do you find any difficulty explaining this to
a subject matter expert?
============Judea