Answer:
The Empirical Rule says that:
outliers are within three standard deviations of the mean.
Explanation:
An outlier is an observed data value which lies some abnormal distance from other values in a population's random sample. The cut-off for an outlier is three standard deviations from the mean in a normal distribution. Therefore, the Empirical Rule concludes that 99.7% of data observed following a normal distribution lies within 3 standard deviations of the mean. In summary, the empirical rule concludes that 68% of the data falls within one standard deviation, 95% percent falls within two standard deviations, while 99.7% falls within three standard deviations from the mean.