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
Mean Hb values in two population groups are compared by 
Select and explain. 
A. Paired t test, B. Unpaired t test, C. Chi square test, D. Fischer test
B: Unpaired t test
Answer: B: Unpaired t test 
Explanation: Ref:Park's Textbook of Preventive and Social Medicine 25th Ed