The Empirical Rule for Normal Distributions

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N(0, 1)

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empirical rule

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N(100, 25)

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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).