Chances are slight that Sandra took the apple. There is almost no chance that Mary got the football. Chances are slight that Brian is gray. It is improbable that if either 'Sandra took the apple' or 'Mary got the football' but not both then Daniel grabbed the milk. It is likely that if 'Sandra took the apple and Brian is gray' then Jeff went to the bedroom. It is probably the case that if 'Mary got the football' or 'Brian is gray' or both then Julius is a rhino.
There is a better than even chance that 'Jeff went to the bedroom' or 'Mary got the football' or both.
There is almost no chance that 'Jeff went to the bedroom' or 'Mary got the football' or both.
There is a better than even chance that 'Jeff went to the bedroom' or 'Mary got 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
  0.1::factA.
  0.02::factB.
  0.1::factC.
  %hop1
  0.1::factX:-xor(factA,factB).
  0.7::factY:-and(factA,factC).
  0.7::factZ:-or(factB,factC).

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

  query(conclusion).
  
'Jeff went to the bedroom' or 'Mary got the football' or both.