Final answer:
An assumption of test-related behavior is that scores on a test can predict other behaviors or real-world outcomes.
Step-by-step explanation:
An assumption of test-related behavior in the context of scores on a test is that scores on a test can predict other behaviors or real-world outcomes. This assumption suggests that a person's performance on a test can provide insights into their behavior or performance in other situations. For example, high scores on a math test may indicate strong problem-solving skills that can be applied to real-world situations.