What percentage of data in a normal distribution falls within 3 standard deviations from the mean?

In a normal distribution, approximately 99.7% of the data falls within three standard deviations from the mean. This concept is part of the empirical rule, often referred to as the 68-95-99.7 rule, which describes the distribution of data in a bell-shaped curve.

According to this rule:

• About 68% of the data lies within one standard deviation from the mean.

• About 95% of the data is found within two standard deviations from the mean.

• Approximately 99.7% of the data falls within three standard deviations.

This distribution represents a significant portion of the total dataset, indicating that values are relatively close to the mean and highlighting the predictability of outcomes in a normal distribution. This characteristic is crucial for statistical analysis and helps in understanding variability and the likelihood of occurrence of various outcomes.