413689 SD standard deviation 23914 3424647 SDNN standard deviation of normal-to-normal intervals 1265 1592021 SDs standard deviations 692 1662488 STD standard deviation 194 440282 SR standard resolution 50 438348 Sr standard deviation 28 2187553 STDEV standard deviation 16 3493710 STDs standard deviations 8 3409574 SD's standard deviations 3 1588142 SDD standard deviation 2 1590140 SDn standard deviations 2 1588132 SDa standard deviations 1 1888589 SDint standard deviations 1 3425697 SDrs standard deviations 1 427131 Si standard deviations 1 445017 st standard deviations 1