Bollinger bands, were developed by JohnBollinger and generally are calculated by plotting two standard deviations above and two standard deviations below a 20-period moving average.
Bollinger bands are used by traders in many different ways, and JohnBollinger himself has his own set of rules and guidelines, which can be found on his Web site, BollingerBands.com.
"With ETFs the individual investor has tools and techniques that were solely the province of sophisticated investors even a year ago, " says JohnBollinger of Bollinger Capital Management, whose Bollinger Bands are a popular method for identifying stocks that have moved outside their normal trading pattern.