Answer and Explanation:
Positive reinforcement involves giving reward for desired behaviour so as to reinforce and make that behavior happen again. Negative reinforcement involves removing bad consequences so as to get desired behaviour or make certain behavior happen again.
In the above, Mr. Kerrigan rewards his son with an ice cream to stop screaming. This is called positive reinforcement. His son Billie, screams to get ice cream, and stops screaming after he gets ice cream. This is negative reinforcement.
Mr. Kerrigan can bring ice cream when he goes to pick up his son Billie from soccer practice. This way Billie won't have to scream when they pass the Dairy Queen sign.