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
How much population falls between median and median plus one standard deviation in a normal distribution ? 
Select and explain. 
A. 0.34, B. 0.68, C. 0.17, D. 0.47
A: 0.34
Answer: A: 0.34 
Explanation: NORMAL DISTRIBUTION

Shape is bilaterally symmetrical
Mean = Median = Mode (coincide)
50% of all values lie above Mean (or Median or Mode)
Mean + 1SD cover 68% values (Mean + 1SD cover 34% values)
Mean + 2SD cover 95% values (Mean + 2SD cover 47.5% values)
Mean + 3SD cover 99% values (Mean + 3SD cover 49.5% values)