In online trading systems, standard deviation is a type of volatility indicators that is used to show and assess periods of volatility and to adjust the settings of other technical indicators, so that the system can react more rapidly to the signals it receives during high periods of high volatility. This includes when price trends change very quickly and investors must promptly open or close a trade.
In general, this indicator is used as a partial component with other indicators. For example, standard deviation can be used to determine the spread between the lower and upper Bollinger Bands.