Standard deviation
Standard deviation measures how spread out a set of numbers is around its average. In investing, it's the usual measure of volatility.
About 68% of normally distributed results fall within one standard deviation of the mean and about 95% within two.
Related terms
- Volatility: Volatility measures how much and how quickly a price moves up and down, usually as the annualized standard deviation of its returns.
Practise with $10,000 in play money
Free. No real money involved.
For learning only. This isn't financial advice.