Question

What percent of a normal population is within 2 standard deviations of the mean?

Answer 1

Approximately 95% of the data fall within two standard deviations of the mean.

Answer 2

In any normal distribution with mean μ and standard deviation σ : Approximately 68% of the data fall within one standard deviation of the mean. Approximately 95% of the data fall within two standard deviations of the mean. Approximately 99.7% of the data fall within three standard deviations of the mean.