Premise: A man in a helmet is riding a bike .
Correct statement: We doubt that a man riding a bike down a street .
Incorrect statement: There is a very good chance that a man riding a bike down a street .
Correct statement: Chances are about even that a man in a helmet riding his mountain bike .
Incorrect statement: It is almost certain that a man in a helmet riding his mountain bike .
Correct statement: We doubt that a person is riding a bike down the street .
Incorrect statement: It is probably the case that a person is riding a bike down the street .
Correct statement: Chances are about even that the man in a helmet is riding a sports bike .
Incorrect statement: There is almost no chance that the man in a helmet is riding a sports bike .
Correct statement: Chances are slight that a man in a red helment is riding a bike .
Incorrect statement: It is probably the case that a man in a red helment is riding a bike .