The Empirical Rule for Normal Distributions

This Demonstration illustrates the "empirical rule" for normal distributions: approximately 68% of the area under the curve falls within one standard deviation of the mean, approximately 95% within two standard deviations, and approximately 99.7% within three standard deviations. Various display options are available (see the Snapshots and the Details section).
  • Contributed by: Marc Brodie
  • (Wheeling Jesuit University)


  • [Snapshot]
  • [Snapshot]
  • [Snapshot]


The region under the curve is interactive. Click any region to shade or unshade it and include or exclude its area from the total.
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