字幕表 動画を再生する 英語字幕をプリント Welcome to the Investors Trading Academy talking glossary of financial terms and events. Our term of the day is “Bollinger Bands” Bollinger Bands are volatility bands placed above and below a moving average. Volatility is based on the standard deviation, which changes as volatility increases and decreases. The bands automatically widen when volatility increases and narrow when volatility decreases. This dynamic nature of Bollinger Bands also means they can be used on different securities with the standard settings. For signals, Bollinger Bands can be used to identify M-Tops and W-Bottoms or to determine the strength of the trend. Standard deviations are a statistical unit of measure describing the dispersal pattern of a data set. By definition, one standard deviation includes about 68% of all data points from the average in what is referred to as a normal distribution pattern, while two standard deviations include about 95% of all data points. When working with Bollinger Bands, it is not necessary for you to calculate standard deviations yourself. You need only understand the theory of how standard deviation sets the range for a dispersal of rates when compared to the moving average, and how this information is used to determine buy and sell channels in the chart. The area between the moving average line and each band produces a range, or channel. The area above the moving average is referred to as the buy channel as prices displayed in this region remain higher than the moving average and suggest upward momentum. Conversely, prices falling below the moving average are in the sell channel as the spot rate is declining more rapidly than the moving average which suggests that the exchange rate has downward momentum.