2.2.7 - The Empirical Rule | STAT 200
online.stat.psu.edu › stat200 › lessonThe Empirical Rule is a statement about normal distributions. Your textbook uses an abbreviated form of this, known as the 95% Rule , because 95% is the most commonly used interval. The 95% Rule states that approximately 95% of observations fall within two standard deviations of the mean on a normal distribution.
Empirical Rule and z-score Probability - Dawn Wright, Ph.D.
www.drdawnwright.com › empirical-rule-and-z-scoreEmpirical Rule. The Empirical Rule applies to a normal, bell-shaped curve than is symmetrical about the mean. It states that within one standard deviation of the mean (both left-side and right-side) there is about 68% of the data; within two standard deviations of the mean (both left-side and right-side) there is about 95% of the data; and within three standard deviations of the mean (both left-side and right-side) there is about 99.7% of the data.