It is probably the case that Winona is a sheep. It is certain that Julius is white. We believe that John discarded the apple. There is a very good chance that if either 'Winona is a sheep' or 'John discarded the apple' but not both then Mary moved to the office. There is a better than even chance that if either 'John discarded the apple' or 'Winona is a sheep' but not both then Brian is yellow. It is almost certain that if 'John discarded the apple and Winona is a sheep' then Lily is a frog.
Chances are slight that either 'Mary moved to the office' or 'Lily is a frog' but not both.
There is a very good chance that either 'Mary moved to the office' or 'Lily is a frog' but not both.
Chances are slight that either 'Mary moved to the office' or 'Lily is a frog' 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.
  1.0::factB.
  0.75::factC.
  %hop1
  0.8::factX:-xor(factA,factC).
  0.6::factY:-xor(factC,factA).
  0.95::factZ:-and(factC,factA).

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

  query(conclusion).
  
Either 'Mary moved to the office' or 'Lily is a frog' but not both.