There is a very good chance that Greg is yellow. It is probable that Winona is a wolf. It is probably the case that Jeff went to the bedroom. It is probably not the case that if either 'Greg is yellow' or 'Jeff went to the bedroom' but not both then Julius is a frog. Chances are about even that if 'Winona is a wolf and Jeff went to the bedroom' then Lily is white. It is unlikely that if 'Jeff went to the bedroom and Winona is a wolf' then Brian is a lion.
There is a better than even chance that 'Greg is yellow and Julius is a frog'.
It is highly unlikely that 'Greg is yellow and Julius is a frog'.
There is a better than even chance that 'Greg is yellow and Julius is a frog'.

  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
  0.8::factA.
  0.7::factB.
  0.7::factC.
  %hop1
  0.25::factX:-xor(factA,factC).
  0.5::factY:-and(factB,factC).
  0.2::factZ:-and(factC,factB).

  %hop2
  conclusion:-and(factA,factX).

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