Final answer:
For a school-age child with ADHD, the nurse should advise parents to consider the child's chronological age when setting goals, providing realistic expectations, and using positive reinforcement appropriately.
Step-by-step explanation:
When advising parents of a school-age child diagnosed with attention deficit hyperactivity disorder (ADHD), the most appropriate statement by the nurse is "Consider your child's chronological age when setting goals." This approach acknowledges the developmental stage of the child and helps in setting realistic and appropriate expectations for their behavior and accomplishments. Negative predictions of success, unpredictability, and conditional affection are not recommended strategies for managing ADHD. Positive reinforcement, such as hugging and praising the child after a task is correctly performed, can be beneficial but should be framed within the context of age-appropriate expectations.