Social & Preventive Medicine In a normal curve, the area of one standard deviation around the mean includes which of the following per cent of values in a distribution – A 0.486 B 0.683 C 0.954 D 0.997 💡 Explanation In a normal curve, the area of one standard deviation around the mean includes which of the following per cent of values in a distribution - ✓ Correct Answer: B. 0.683