There is almost no chance that Lily is a rhino. It is probable that Emily is a mouse. There is a better than even chance that Fred discarded the apple. We doubt that if either 'Fred discarded the apple' or 'Lily is a rhino' but not both then Brian is a frog. It is improbable that if either 'Emily is a mouse' or 'Lily is a rhino' but not both then Julius is gray. There is a very good chance that if either 'Lily is a rhino' or 'Fred discarded the apple' but not both then Jason is tired.
There is a very good chance that either 'Fred discarded the apple' or 'Jason is tired' but not both.
It is improbable that either 'Fred discarded the apple' or 'Jason is tired' but not both.
There is a very good chance that either 'Fred discarded the apple' or 'Jason is tired' 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
  0.02::factA.
  0.7::factB.
  0.6::factC.
  %hop1
  0.2::factX:-xor(factC,factA).
  0.1::factY:-xor(factB,factA).
  0.8::factZ:-xor(factA,factC).

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

  query(conclusion).
  
Either 'Fred discarded the apple' or 'Jason is tired' but not both.