It is almost certain that Julius is a swan. It is highly unlikely that Mary went to the hallway. There is a better than even chance that John picked up the milk. It is likely that if 'Mary went to the hallway and Julius is a swan' then Sandra left the football. We believe that if 'Mary went to the hallway and John picked up the milk' then Brian is white. It is almost certain that if 'Julius is a swan' or 'John picked up the milk' or both then Lily is a rhino.
Chances are about even that 'Mary went to the hallway' or 'Sandra left the football' or both.
It is highly unlikely that 'Mary went to the hallway' or 'Sandra left the football' or both.
Chances are about even that 'Mary went to the hallway' or 'Sandra left the football' 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
  0.95::factA.
  0.05::factB.
  0.6::factC.
  %hop1
  0.7::factX:-and(factB,factA).
  0.75::factY:-and(factB,factC).
  0.95::factZ:-or(factA,factC).

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

  query(conclusion).
  
'Mary went to the hallway' or 'Sandra left the football' or both.