Bollinger Bands

Parameter Default Acceptable Values

Length

20 1 to 1,000

Std Dev 

2.00 Any positive number

Source

Close    Open, High, Low, or Close

Example

200 Period Bollinger Band with 2 standard deviations: 20, 2, Close

 45 Period Bollinger Band with 2 standard deviations: 20, 2, Open

Description

Bollinger Bands and Envelopes are similar.  Bollinger Bands are  calculated using standard deviations on the current moving average over the specified interval Length. Note that there is no Interval given, all values are with respect to the current displayed time frame of the chart. The lines produced represent the volatility of the underlying security.  High volatility is depicted by lines spread far apart, low volatility is depicted by the lines coming closer together.  Sometimes market reversals occur near the upper and lower lines. 

ErlangerQuote Special

The study label, the text box that shows its current value, can be placed on either the left or the right axis.