In a normally distributed population, the number of observations falling within the range Mean ± 1 S.D. is approximately __%?

Correct option is C

· In a normal distribution, approximately 68% of the observations fall within one standard deviation (±1 SD) of the mean.
· 95% of the data falls within two standard deviations (±2 SD), and 99.7% falls within three standard deviations (±3 SD).
· This concept follows the Empirical Rule (68-95-99.7 rule) in statistics.