Standard deviation is a measurement of market volatility. Learn how investors use standard deviation in the MoneySense Glossary. Standard deviation (σ) is an investing metric used to measure the ...

The empirical rule is also used as a rough way to test a distribution's "normality." If too many data points fall outside the three standard deviation boundaries, this suggests that the ...

They are important to help determine volatility and the distribution of returns. However, there are inherent differences between the two. While standard deviation measures the square root of the ...