It is certain that Brian is yellow. It is probably the case that Fred is in the school. It is probably not the case that Lily is gray. We believe that if 'Brian is yellow' or 'Fred is in the school' or both then John left the football. It is probable that if 'Lily is gray and Brian is yellow' then Mary went to the bedroom. There is almost no chance that if 'Brian is yellow and Lily is gray' then Jeff dropped the apple.
Chances are about even that 'Brian is yellow' or 'Fred is in the school' or both.
It is certain that 'Brian is yellow' or 'Fred is in the school' or both.
Chances are about even that 'Brian is yellow' or 'Fred is in the school' or both.

  and(A,B) :- A,B.
  or(A,B) :- A;B.
  nand(A,B) :- not(and(A,B)).
  nor(A,B) :- not(or(A,B)).
  xor(A,B) :- or(A,B), nand(A,B).

  %hop0
  1.0::factA.
  0.7::factB.
  0.25::factC.
  %hop1
  0.75::factX:-or(factA,factB).
  0.7::factY:-and(factC,factA).
  0.02::factZ:-and(factA,factC).

  %hop2
  conclusion:-or(factA,factB).

  query(conclusion).
  
'Brian is yellow' or 'Fred is in the school' or both.