We doubt that Sandra left the milk. It is probable that Daniel got the football. It is unlikely that Lily is green. It is probably not the case that if 'Lily is green and Daniel got the football' then Brian is a frog. There is a better than even chance that if 'Sandra left the milk and Lily is green' then Jeff went to the hallway. It is improbable that if 'Lily is green' or 'Daniel got the football' or both then Julius is a swan.
It is probable that 'Daniel got the football' or 'Brian is a frog' or both.
It is probable that 'Daniel got the football' or 'Brian is a frog' or both.
It is impossible that 'Daniel got the football' or 'Brian is a frog' 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
  0.2::factA.
  0.7::factB.
  0.2::factC.
  %hop1
  0.25::factX:-and(factC,factB).
  0.6::factY:-and(factA,factC).
  0.1::factZ:-or(factC,factB).

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

  query(conclusion).
  
'Daniel got the football' or 'Brian is a frog' or both.