BOLLinger Band Index, or Boll Index, is called Bollinger in English.

Band ",Bollinger band (boll) by John.

Mr. Brin created it, using statistical principles, to find out the standard deviation of stock price and its confidence interval, so as to determine the fluctuation interval and future trend of stock price, and to display the safe high and low price of stock price with bands, so it is also called Bollinger Band. The upper and lower limits are not fixed, but change with the stock price rolling. Like Mike's indicator, the Brin indicator belongs to the path indicator, and the stock price fluctuates in the upper and lower range. The width of this band varies with the fluctuation of stock price. When the stock price rises and falls, the banded region becomes wider, the fluctuation range becomes narrower and the banded region becomes narrower when it is consolidated.

Bollinger Band Index (boll) is to calculate the "standard deviation" of the stock price, and then find the "trust interval" of the stock price. The indicator has drawn three lines on the map, in which the upper and lower lines can be regarded as the pressure line and the support line of the stock price respectively, and there is an average line of the stock price between the two lines, and the parameter of the Bollinger Band indicator is preferably set to 20. Generally speaking, the stock price will run in the channel formed by the pressure line and the support line.