It is probable that John took the football. Chances are about even that Greg is white. It is probable that Jeff moved to the garden. It is improbable that if 'Greg is white and John took the football' then Mary is in the bathroom. It is probably the case that if either 'Greg is white' or 'Jeff moved to the garden' but not both then Julius is a frog. Chances are about even that if either 'Greg is white' or 'Jeff moved to the garden' but not both then Bernhard is a lion.
It is almost certain that 'Mary is in the bathroom' or 'Julius is a frog' or both.
Chances are about even that 'Mary is in the bathroom' or 'Julius is a frog' or both.
It is almost certain that 'Mary is in the bathroom' or 'Julius 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.
  0.5::factB.
  0.7::factC.
  %hop1
  0.1::factX:-and(factB,factA).
  0.7::factY:-xor(factB,factC).
  0.5::factZ:-xor(factB,factC).

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

  query(conclusion).
  
'Mary is in the bathroom' or 'Julius is a frog' or both.