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: Dental
Chi square test is applied to test the independence of cross distribution of two variables and each of them should have 
Select and explain. 
A. Equal number of cases, B. Mutually exclusive cases, C. Normal distribution, D. Non-mutually exclusive cases
B: Mutually exclusive cases
Answer: B: Mutually exclusive cases 
Explanation: None