There is a better than even chance that Emily is a mouse. Chances are about even that Sandra put down the milk. It is probable that John went to the hallway. Chances are slight that if 'Emily is a mouse' or 'John went to the hallway' or both then Greg is gray. There is almost no chance that if 'John went to the hallway' or 'Emily is a mouse' or both then Bernhard is a frog. It is likely that if 'Sandra put down the milk' or 'John went to the hallway' or both then Julius is white.
It is improbable that 'Emily is a mouse' or 'Sandra put down the milk' or both.
There is a very good chance that 'Emily is a mouse' or 'Sandra put down the milk' or both.
It is improbable that 'Emily is a mouse' or 'Sandra put down the milk' 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
  0.6::factA.
  0.5::factB.
  0.7::factC.
  %hop1
  0.1::factX:-or(factA,factC).
  0.02::factY:-or(factC,factA).
  0.7::factZ:-or(factB,factC).

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

  query(conclusion).
  
'Emily is a mouse' or 'Sandra put down the milk' or both.