It is unlikely that Mary went to the office. Chances are about even that Julius is a swan. Chances are slight that Jason is tired. It is likely that if 'Mary went to the office and Julius is a swan' then Brian is green. It is almost certain that if either 'Julius is a swan' or 'Jason is tired' but not both then Sandra got the football. It is highly unlikely that if 'Jason is tired' or 'Julius is a swan' or both then Bernhard is a rhino.
There is a better than even chance that 'Julius is a swan' or 'Jason is tired' or both.
There is a better than even chance that 'Julius is a swan' or 'Jason is tired' or both.
It is improbable that 'Julius is a swan' or 'Jason is tired' or 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
  0.2::factA.
  0.5::factB.
  0.1::factC.
  %hop1
  0.7::factX:-and(factA,factB).
  0.95::factY:-xor(factB,factC).
  0.05::factZ:-or(factC,factB).

  %hop2
  conclusion:-or(factB,factC).

  query(conclusion).
  
'Julius is a swan' or 'Jason is tired' or both.