There is little chance that Brian is gray. Chances are about even that Jason is tired. There is a better than even chance that Julius is a frog. It is highly likely that if either 'Julius is a frog' or 'Jason is tired' but not both then Greg is white. It is probably not the case that if 'Julius is a frog and Brian is gray' then Daniel put down the milk. There is a better than even chance that if 'Jason is tired and Julius is a frog' then Bill went to the garden.
Chances are about even that either 'Daniel put down the milk' or 'Jason is tired' but not both.
Chances are about even that either 'Daniel put down the milk' or 'Jason is tired' but not both.
It is almost certain that either 'Daniel put down the milk' 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
  0.1::factA.
  0.5::factB.
  0.6::factC.
  %hop1
  0.9::factX:-xor(factC,factB).
  0.25::factY:-and(factC,factA).
  0.6::factZ:-and(factB,factC).

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

  query(conclusion).
  
Either 'Daniel put down the milk' or 'Jason is tired' but not both.