Chances are slight that Winona is a mouse. It is probably the case that Jessica is a mouse. There is little chance that Greg is a lion. There is almost no chance that if 'Winona is a mouse and Jessica is a mouse' then Sumit is bored. It is improbable that if 'Greg is a lion and Winona is a mouse' then Jeff moved to the garden. It is probably not the case that if 'Jessica is a mouse' or 'Greg is a lion' or both then Mary got the football.
It is unlikely that either 'Sumit is bored' or 'Mary got the football' but not both.
It is unlikely that either 'Sumit is bored' or 'Mary got the football' but not both.
It is likely that either 'Sumit is bored' or 'Mary got the football' 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
  0.1::factA.
  0.7::factB.
  0.1::factC.
  %hop1
  0.02::factX:-and(factA,factB).
  0.1::factY:-and(factC,factA).
  0.25::factZ:-or(factB,factC).

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

  query(conclusion).
  
Either 'Sumit is bored' or 'Mary got the football' but not both.