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.