Bollinger Bands (BB) are constructed using the following formula:
±1σ: Simple Moving Average (SMA) ± Standard Deviation
±2σ: Simple Moving Average ± (Standard Deviation × 2)
±3σ: Simple Moving Average ± (Standard Deviation × 3)
The probability of price movement staying within each band is as follows:
±1σ: 68.26%
±2σ: 95.44%
±3σ: 99.74%