When the price line is above the middle band of the Bollinger Bands, the trend is strong; when the price line is below the middle band of the Bollinger Bands, the trend is weak. The two extremes of the Bollinger Bands are the upper band and the lower band, representing very strong and very weak respectively. When the price crosses above the upper band, it is a sell signal; when the price crosses below the lower band, it is a buy signal; when the price crosses from below to above the middle band, it is a long signal; when the price crosses from above to below the middle band, it is a sell signal. This is the basic usage of the Bollinger Bands.
