It is probable that Winona is a wolf. It is likely that Mary moved to the office. It is probable that Jason is bored. We believe that if 'Winona is a wolf and Jason is bored' then Jessica is a cat. It is likely that if 'Winona is a wolf' or 'Mary moved to the office' or both then Bernhard is a swan. We doubt that if either 'Jason is bored' or 'Winona is a wolf' but not both then Julius is a frog.
Chances are about even that either 'Winona is a wolf' or 'Jason is bored' but not both.
Chances are about even that either 'Winona is a wolf' or 'Jason is bored' but not both.
It is highly unlikely that either 'Winona is a wolf' or 'Jason is bored' 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.
  0.7::factB.
  0.7::factC.
  %hop1
  0.75::factX:-and(factA,factC).
  0.7::factY:-or(factA,factB).
  0.2::factZ:-xor(factC,factA).

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

  query(conclusion).
  
Either 'Winona is a wolf' or 'Jason is bored' but not both.