Standard deviation is a statistical measure that quantifies the degree to which individual data points in a dataset such as a stock's daily returns deviate from the mean (average) value. In financial markets, standard deviation is used as a measure of volatility: a high standard deviation indicates that prices are moving widely and unpredictably around their average, while a low standard deviation suggests stability. It forms the mathematical foundation of tools like Bollinger Bands, where the outer bands are typically set two standard deviations from the moving average. Portfolio managers also use standard deviation to measure and compare the total risk of different investments or fund strategies over a given time period.
For android only
