This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Biostatistics, Subject name: Social & Preventive Medicine
Which of the following is a pre - requissite for the Chi square test to compare- 
Select and explain. 
A. Both sample should be mutually exclusive, B. Both sample need not be mutually exclusive, C. Normal distribution, D. All of the above
A: Both sample should be mutually exclusive
Answer: A: Both sample should be mutually exclusive 
Explanation: .