Answer:
representativeness heuristic
Explanation:
Based on the information provided within the question it can be said that in this scenario Jaden seems to have relied on the representativeness heuristic. This term refers to assessing something based on the similarity of the objects and organizing them based on that specific category. Which is what Jaden has done in this scenario by assuming that he had appendicitis solely due to the fact that he had one similar symptom.