Answer:
99.7%
Step-by-step explanation:
Refer to the attached image showing the empirical method:
The red section shows all the data within one standard deviation of the mean. According to the empirical rule, this is 68 % of the data.
The yellow section shows all the data within two standard deviations of the mean, which is 95 % of the data.
The blue section shows all the data within three standard deviations of the mean, which is 99.7 % of the data.
Thus, the data within three sigma limits, is 99.7%, of the observed values.
