Bollinger Bands
A moving average with bands set by the standard deviation.
Inputs
| Name | Type | Default | Range |
|---|---|---|---|
| source | source | close | |
| period | int | 20 | 1 to 5000 |
| deviations | float | 2 | 0 to 10 |
Outputs
| Name | Type | Required | Description |
|---|---|---|---|
| upper | value | Optional | color theme.series_b, style line, width 1 |
| middle | value | Optional | color theme.series_a, dash dash, style line, width 1 |
| lower | value | Optional | color theme.series_b, style line, width 1 |
- Warm-up
- period - 1 bars (19 at the defaults)
- Repaints
- No
- Parity
- TA-Lib, within 1e-9
Formula
middle = the simple average of the source over period
upper = middle + deviations * the population standard deviation of the same window, lower = middle - deviations * the same