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# bolling

Bollinger band chart

## Syntax

```bolling(Asset, Samples, Alpha, Width)
[Movavgv, UpperBand, LowerBand] = bolling(Asset, Samples, Alpha,Width)
```

## Arguments

 Asset Vector of asset data. Samples Number of samples to use in computing the moving average. Alpha (Optional) Exponent used to compute the element weights of the moving average. Default = 0 (simple moving average). Width (Optional) Number of standard deviations to include in the envelope. A multiplicative factor specifying how tight the bands should be around the simple moving average. Default = 2.

## Description

bolling(Asset, Samples, Alpha, Width) plots Bollinger bands for given Asset data. This form of the function does not return any data.

[Movavgv, UpperBand, LowerBand] = bolling(Asset, Samples, Alpha, Width) returns Movavgv with the moving average of the Asset data, UpperBand with the upper band data, and LowerBand with the lower band data. This form of the function does not plot any data.

 Note   The standard deviations are normalized by N-1, where N = the sequence length.

## Examples

If Asset is a column vector of closing stock prices

```bolling(Asset, 20, 1)
```

plots linear 20-day moving average Bollinger bands based on the stock prices.

```[Movavgv, UpperBand, LowerBand] = bolling(Asset, 20, 1)
```

returns Movavgv, UpperBand, and LowerBand as vectors containing the moving average, upper band, and lower band data, without plotting the data.