In: Statistics and Probability
What is meant by empirical rule or 68 – 95 – 99.7 rule in statistics ?
In statistics, empirical rule refers to a rule according to which 68%, 95% and 99.7% of observations lie within the one standard deviation, two standard deviations and three standard deviations from the mean (µ) in a normal or Guassian distribution respectively. Thus, the respective intervals are µ ± σ, µ ± 2σ, and µ ± 3σ. Because the rule basically came into existence thanks to actual observations made it has been termed empirical rule.
This rule is also referred to as the 68 - 95 - 99.7 rule to help memorise the corresponding percentages of observations within the specified interval estimates. As almost whole dataset lies within three standard deviations of the mean in the normal distribution, it is also sometimes known as three-sigma rule.
Empirical rule refers to a rule according to which 68%, 95% and 99.7% of observations lie within the one standard deviation, two standard deviations and three standard deviations from the mean (µ) in a normal or Guassian distribution respectively.