This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
[{'content': '. Test used to study the ordinal data of two independent groups which are not normally distributed? \nSelect and explain. \nA. Student t test, B. z test, C. Single line analysis of variance, D. Wilcoxan signed rank test', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]