The normal distribution is a bell-shaped curve. Most of the data points are around the median. Hence approximately 68 per cent of the data is around the median. Since there is no skewness and its bell-shaped.

The 68-95-99.7 (empirical) rule, also known as the three-sigma rule or the 68% rule, is a statistical guideline often applied to normal distributions. It states that:

Approximately 68% of the data falls within one standard deviation (σ) of the mean (µ).
Approximately 95% falls within two standard deviations.
Approximately 99.7% falls within three standard deviations.

In the context of a normal distribution, about 68% of the data points are expected to fall within one standard deviation from the mean in either direction. This rule provides a quick and useful way to understand the spread of data in a normal distribution.