Final answer:
The assumption is baseless. A person's performance on a math exam is not a reliable indicator of their overall ability compared to the rest of the class.
Step-by-step explanation:
The assumption that the student is better than the rest of the class based on performing well on a math exam is baseless. It is a hasty generalization to conclude that one's performance on a single exam is indicative of their overall ability compared to the entire class. A person's performance on a math exam can be influenced by various factors such as exam difficulty, preparation, and personal strengths.