It is probable that Bernhard is gray. It is certain that Jessica is a sheep. It is unlikely that Winona is a mouse. There is almost no chance that if 'Bernhard is gray' or 'Jessica is a sheep' or both then John discarded the milk. Chances are about even that if either 'Bernhard is gray' or 'Jessica is a sheep' but not both then Brian is yellow. It is improbable that if 'Jessica is a sheep and Bernhard is gray' then Greg is a lion.
There is little chance that 'Winona is a mouse and Bernhard is gray'.
There is little chance that 'Winona is a mouse and Bernhard is gray'.
We believe that 'Winona is a mouse and Bernhard is gray'.

  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.
  1.0::factB.
  0.2::factC.
  %hop1
  0.02::factX:-or(factA,factB).
  0.5::factY:-xor(factA,factB).
  0.1::factZ:-and(factB,factA).

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

  query(conclusion).
  
'Winona is a mouse and Bernhard is gray'.