<prompt> Area falling under 2 S.D. curve would be around -66955799  <response>: Ref: Parks 23rd edition pg 848 The several measures of variation or dispersion of which the following are widely known : RangeThe mean or Average detion The standard detion . Ref:Parks 23rd edition pg 849. 1SD : confidence limit 68 2SD : confidence limit 95 3SD : confidence limit 99.7 