What percentage of data falls within three standard deviations of the mean according to the Empirical Rule?

The Empirical Rule, also known as the 68-95-99.7 rule, applies to data that follows a normal distribution. According to this rule, approximately 99.7% of data points will fall within three standard deviations from the mean. This statistical principle highlights how most data in a normally distributed set is contained within this range, indicating that very few observations lie far from the mean.

In contrast, the percentages corresponding to one and two standard deviations from the mean are 68% and 95%, respectively, which is why those options do not accurately represent the data falling within three standard deviations. A claim of 100% would imply that all data points fall within that range, which is not realistic for a normal distribution where outliers can exist beyond three standard deviations. Thus, 99.7% is indeed the correct figure that encapsulates the data falling within three standard deviations of the mean in the context of the Empirical Rule.