It is likely that Julius is a frog. There is little chance that Bill moved to the office. It is likely that Greg is a rhino. Chances are slight that if 'Bill moved to the office and Julius is a frog' then John picked up the apple. It is unlikely that if 'Bill moved to the office and Greg is a rhino' then Bernhard is gray. Chances are about even that if either 'Bill moved to the office' or 'Julius is a frog' but not both then Winona is a mouse.
It is likely that either 'Julius is a frog' or 'Bernhard is gray' but not both.
It is likely that either 'Julius is a frog' or 'Bernhard is gray' but not both.
There is almost no chance that either 'Julius is a frog' or 'Bernhard is gray' but not 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.
  0.1::factB.
  0.7::factC.
  %hop1
  0.1::factX:-and(factB,factA).
  0.2::factY:-and(factB,factC).
  0.5::factZ:-xor(factB,factA).

  %hop2
  conclusion:-xor(factA,factY).

  query(conclusion).
  
Either 'Julius is a frog' or 'Bernhard is gray' but not both.