Bollinger

These bands show whether prices are high or low relative to normal trading ranges.
Bollinger suggests the 20 day simple moving average with ±2standard deviations for intermediate term trend. For short term trend, Bollinger suggests a 10 day SMA with 1.5 standard deviations.

• When the bands narrow, there is a tendency for sharp price changes to follow
• If price exceeds a band, the trend is expected to continue.
• When the price traces out of a reversal formation after it has crossed outside a band, expect a trend reversal.