Since this consists of \(\displaystyle{3}\sigma\) below and \(\displaystyle{3}\sigma\) above \(\displaystyle\mu\), the data values are expected to fall in the range of \(\displaystyle{3}\sigma+{3}\sigma={6}\sigma\).

\(\displaystyle\sigma={10}\)

\(\displaystyle{6}\sigma={6}\times{10}={60}\)

The normal distribution is approximately 60.