# Linear regression slope

`linreg_slope`

How much the fitted line rises or falls per bar.

## Inputs

| Name | Type | Default | Range |
| --- | --- | --- | --- |
| source | source | close |  |
| period | int | 14 | 2 to 5000 |

## Outputs

| Name | Kind |
| --- | --- |
| linreg_slope | value |

Warm-up: period - 1 bars (13 at the defaults).

Repaints: No.

## Formula

Fit a straight line by least squares to the last period values, with t = 0 at the oldest.

b = (period * sum(t*y) - sum(t) * sum(y)) / (period * sum(t^2) - sum(t)^2)

a = (sum(y) - b * sum(t)) / period

Slope = b