Social & Preventive Medicine Measures of Central Tendency and Distribution 373ea730 Area between one standard deviation on either side of mean in normal distribution curve is: A 62% B 68% C 90% D 99% High-Yield Explanation Ans. is 'b' i.e. 68% * mean +- 1SD-68.3%* mean +- 2SD-95.4%* mean +- 3SD-99.7%