It is likely that Mary went to the bedroom. It is probable that John discarded the apple. We doubt that Winona is a wolf. It is impossible that if 'Mary went to the bedroom and Winona is a wolf' then Julius is yellow. Chances are slight that if 'Winona is a wolf and John discarded the apple' then Lily is white. There is little chance that if 'John discarded the apple' or 'Winona is a wolf' or both then Greg is a frog.
It is highly likely that 'Julius is yellow' or 'Greg is a frog' or both.
Chances are slight that 'Julius is yellow' or 'Greg is a frog' or both.
It is highly likely that 'Julius is yellow' or 'Greg 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
  0.7::factA.
  0.7::factB.
  0.2::factC.
  %hop1
  0.0::factX:-and(factA,factC).
  0.1::factY:-and(factC,factB).
  0.1::factZ:-or(factB,factC).

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

  query(conclusion).
  
'Julius is yellow' or 'Greg is a frog' or both.