# Standard Deviation Channels

get_stdev_channels(quotes, lookback_periods=20, standard_deviations=2)

## Parameters

name | type | notes |
---|---|---|

`quotes` | Iterable[Quote] | Iterable of the Quote class or its sub-class. • See here for usage with pandas.DataFrame |

`lookback_periods` | int, Optional, default 20 | Size (`N` ) of the evaluation window. Must be `None` or greater than 1 to calculate. A `None` value will produce a full `quotes` evaluation window (see below). |

`standard_deviations` | int, default 2 | Width of bands. Standard deviations (`D` ) from the regression line. Must be greater than 0. Default is 2. |

### Historical quotes requirements

You must have at least `N`

periods of `quotes`

to cover the warmup periods.

`quotes`

is an `Iterable[Quote]`

collection of historical price quotes. It should have a consistent frequency (day, hour, minute, etc). See the Guide for more information.

## Return

```
StdevChannelsResults[StdevChannelsResult]
```

- This method returns a time series of all available indicator values for the
`quotes`

provided. `StdevChannelsResults`

is just a list of`StdevChannelsResult`

.- It always returns the same number of elements as there are in the historical quotes.
- It does not return a single incremental indicator value.
- Up to
`N-1`

periods will have`None`

values since there’s not enough data to calculate.

👉

Repaint warning: Historical results are a function of the current period window position and will fluctuate over time. Recommended for visualization; not recommended for backtesting.

### StdevChannelsResult

name | type | notes |
---|---|---|

`date` | datetime | Date |

`center_line` | float, Optional | Linear regression line (center line) |

`upper_channel` | float, Optional | Upper line is `D` standard deviations above the center line |

`lower_channel` | float, Optional | Lower line is `D` standard deviations below the center line |

`break_point` | bool | Helper information. Indicates first point in new window. |

### Utilities

See Utilities and Helpers for more information.

## Example

```
from stock_indicators import indicators
# This method is NOT a part of the library.
quotes = get_historical_quotes("SPY")
# calculate StdDevChannels(20,2)
results = indicators.get_stdev_channels(quotes, 20,2)
```

## Alternative depiction for full quotes variant

If you specify `None`

for the `lookback_periods`

, you will get a regression line over the entire provided `quotes`

.

## About Standard Deviation Channels

Standard Deviation Channels are based on an linear regression centerline and standard deviations band widths. [Discuss] 💬