# Empirical Rule Calculation

Empirical rule is the statistical rule for a normal distribution determined with the mean and the standard deviation. According to it, 68 % of data falls within first SD, 95 % within first two SD and 99.7 % within first three SD's. Hence it is also known as 68-95-99.7 or three sigma rule. Find the Empirical rule for the given set of data using this calculator.
The empirical rule works because it allows to estimate probabilities very quickly when someone dealing with a normal distribution. We often create ranges using standard deviation, so knowing what percentage of cases fall within 1, 2 and 3 standard deviations can be useful.

Total Numbers
Mean (Average)
Standard Deviation
Empirical Rule at 68% falls between
Empirical Rule at 95% falls between
Empirical Rule at 97.7% falls between
The empirical rule referred as three-sigma rule or 68-95-99.7 rule, it is a statistical rule which states that for a normal distribution, almost all observed data will fall within three standard deviations (denoted by σ) of the mean or average (denoted by µ).
The empirical value is :
a. derived from or relating to experiment and observation rather than theory,
b. based on practical experience rather than scientific proof and
c. (Philosophy) a (of knowledge) derived from experience rather than by logic from first principles.
Empirical means “based on observation” : The empirical rule come from observations. The Normal/Gaussian distribution is the most common type of data distribution. All of the measurements are computed as distances from the mean and are reported in standard deviations.