Bollinger Bands

boll

Function Name: boll

Tags: Bands

Category: Trend, Volatility

The Bollinger Bands indicator is one of the most commonly used technical indicators. It draws two bands that are plotted usually two standard deviations above and below a moving average. An upper band is plotted a specified number of standard deviations above this average and a lower band is plotted a specified number of standard deviations below the average.

The Bollinger Bands indicator combines the trend identifying aspects of a moving average with a dynamic factor, each market's own volatility, to plot an envelope. The distance between the bands is, therefore, a reflection of volatility. During sideways periods, prices reaching the bands may indicate overbought or oversold conditions. Strong movement up through the upper band or down through the lower band may indicate the beginning of a trend.

 

Author:   John Bollinger

Link:       http://www.investopedia.com/terms/b/bollingerbands.asp

 

Parameters

period

 

Default Value: 20  |  Minimum: 1  |  Maximum: 9999

 

Type: Numeric

deviation1

 

Default Value: 2  |  Minimum: 0  |  Maximum: 5

 

Type: Numeric

deviation2

 

Default Value: -2  |  Minimum: -5  |  Maximum: 0

 

Type: Numeric