TTR (version 0.21-1)

bollingerBands: Bollinger Bands

Description

Bollinger Bands are a way to compare a security's volatility and price levels over a period of time. Developed by John Bollinger.

Usage

BBands(HLC, n=20, maType, sd=2, ...)

Arguments

HLC

Object that is coercible to xts or matrix and contains High-Low-Close prices. If only a univariate series is given, it will be used. See details.

n

Number of periods for moving average.

maType

A function or a string naming the function to be called.

sd

The number of standard deviations to use.

...

Other arguments to be passed to the maType function.

Value

• A object of the same class as HLC or a matrix (if try.xts fails) containing the columns:
• dn
  The lower Bollinger Band.
• ma
  The middle Moving Average (see notes).
• up
  The upper Bollinger Band.
• pctB
  The %B calculation.

Details

Bollinger Bands consist of three lines:

The middle band is generally a 20-period SMA of the typical price ([high + low + close]/3). The upper and lower bands are sd standard deviations (generally 2) above and below the MA.

The middle band is usually calculated using the typical price, but if a univariate series (e.g. Close, Weighted Close, Median Price, etc.) is provided, it will be used instead.

References

The following site(s) were used to code/document this indicator: http://www.fmlabs.com/reference/Bollinger.htm http://www.fmlabs.com/reference/BollingerWidth.htm http://www.equis.com/Customer/Resources/TAAZ/?c=3&p=36 http://www.linnsoft.com/tour/techind/bb.htm http://stockcharts.com/education/IndicatorAnalysis/indic_Bbands.html http://stockcharts.com/education/IndicatorAnalysis/indic_BBWidth.htm

See Also

See EMA, SMA, etc. for moving average options; and note Warning section.

Examples

## The examples below show the differences between using a
  ## High-Low-Close series, and just a close series when
  ## calculating Bollinger Bands.
  data(ttrc)
  bbands.HLC <- BBands( ttrc[,c("High","Low","Close")] )
  bbands.close <- BBands( ttrc[,"Close"] )