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
If the distribution of intraocular pressure (IOP) seen in 100 glaucoma patients has an average 30 mm with an SD of 1, what is the lower limit of the average that can be expected 95% of times - 
Select and explain. 
A. 28, B. 26, C. 32, D. 25
A: 28
Answer: A: 28 
Explanation: In the given question, Mean (μ) = 30 mm and SD (σ) = 1.0 mm
Thus, 95% values are contained in the range of Mean ± 2 SD (µ ± 2s) or 30 ± 2 (1)
So, 95% values are contained in the range 30 – 2 mm and 30 + 2 mm OR between 28 and 30 mm.