iSixSigma

Empirical Rule

Definition of Empirical Rule:

For data sets having a normal, bell-shaped distribution, the following properties apply:

  • About 68% of all values fall within 1 standard deviation of the mean
  • About 95% of all values fall within 2 standard deviation of the mean
  • About 99.7% of all values fall within 3 standard deviation of the mean.
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