It is highly unlikely that Sumit is bored. It is unlikely that Fred is in the office. We doubt that Brian is yellow. It is unlikely that if either 'Fred is in the office' or 'Sumit is bored' but not both then Emily is a mouse. It is improbable that if 'Fred is in the office and Brian is yellow' then Julius is gray. We doubt that if 'Brian is yellow and Fred is in the office' then Sandra left the milk.
It is unlikely that either 'Fred is in the office' or 'Sandra left the milk' but not both.
It is unlikely that either 'Fred is in the office' or 'Sandra left the milk' but not both.
It is almost certain that either 'Fred is in the office' or 'Sandra left the milk' 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
  0.05::factA.
  0.2::factB.
  0.2::factC.
  %hop1
  0.2::factX:-xor(factB,factA).
  0.1::factY:-and(factB,factC).
  0.2::factZ:-and(factC,factB).

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

  query(conclusion).
  
Either 'Fred is in the office' or 'Sandra left the milk' but not both.