The empirical rule states that for normally distributed data, almost all of the data will fall within 3 standard deviations of the mean. This is broken into three parts.
- 68% of the data falls within the first standard deviation from the mean.
- 95% fall within two standard deviations.
- 99.7% fall within three standard deviations.
Summarized from https://www.statisticshowto.datasciencecentral.com/empirical-rule-2/
