It is probably not the case that Jeff left the apple. It is probable that Winona is a cat. It is probably the case that Bernhard is green. It is probably not the case that if either 'Bernhard is green' or 'Jeff left the apple' but not both then Lily is yellow. There is a better than even chance that if 'Bernhard is green and Winona is a cat' then John went to the kitchen. It is almost certain that if 'Jeff left the apple and Winona is a cat' then Brian is a frog.
Chances are about even that either 'Bernhard is green' or 'John went to the kitchen' but not both.
Chances are about even that either 'Bernhard is green' or 'John went to the kitchen' but not both.
It is certain that either 'Bernhard is green' or 'John went to the kitchen' 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
  0.25::factA.
  0.7::factB.
  0.7::factC.
  %hop1
  0.25::factX:-xor(factC,factA).
  0.6::factY:-and(factC,factB).
  0.95::factZ:-and(factA,factB).

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

  query(conclusion).
  
Either 'Bernhard is green' or 'John went to the kitchen' but not both.