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
A chest physician observed that the distribution of forced expiratory volume (FEV) in 300 smokers had a median value of 2.5 litres with the first and third quailes being 1.5 and 4.5 litres respectively. Based on this data now many persons in the sample ra eexpectable have a FEV between 1.5 and 4.5 litres- 
Select and explain. 
A. 75, B. 150, C. 225, D. 300
B: 150
Answer: B: 150 
Explanation: Here, it&;s given 1st and 3rd quaile, which includes 50% values . Here total is 300. So 50% means 150