BOLLINGER(values; period; deviation)

The 'values' argument must be an array.
The 'period' defines the period for the function - it must be a constant greater or equal to 1.
The 'deviation' defines the number of standard deviations the band is offset from the simple moving average of 'values'. For the upper band this must be a positive value and for the lower band - a negative value.

The result is an array. The first 'period' elements of the result are marked as invalid.

Bollinger bands are displayed at a given number of standard deviations from a moving average of a price. Since standard deviation is a measure of volatility, the bands are self-adjusting: widening during volatile markets and contracting during calmer periods. Bollinger Bands were created by John Bollinger.

To display the two Bollinger bands you can use two line series (one for the upper band and one for the lower band) or a single Hi-Low series.
For the upper band use the following expression: "BOLLINGER(values, 20, 2)".
For the lower band use the following expression: "BOLLINGER(values, 20, -2)".

Mr. Bollinger recommends using "20" for the number of periods in the moving average, and using 2 standard deviations. He has also found that moving averages of less then 10 periods do not work very well.

Windows Forms: All Examples\Data Manipulation\Functions\Financial\Range Indicators
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