Bollinger Bands
A moving average with a standard-deviation band either side.
Formula
Middle = SMA(20); Bands = Middle ± 2 × σ(20)
How to read it
Touching a band is not by itself a signal: in a strong trend price walks along it. Bands squeezing together mark low volatility, which tends to precede a larger move.
How to use it
Measures how stretched a price is against its own recent volatility.
In Kereon
Charts · Superchart. Defaults 20 and 2 on the close. Population deviation (÷ N), Bollinger's own definition.
Also called: bollinger, bands, std dev bands.