# Inertia

``` Inertia ( IDataHolder data, int length); ```

## Description

Draws the linear regression curve using the least-squares method to approximate data for each set of bars defined by the `length` parameter. The resulting interpolation function for each set of bars is defined by equation: `y = a * current_bar + b` . See the following example for details.

## Input parameters

Parameter Default value Description
data - Defines the variable for which the linear regression curve is calculated.
length - Defines the period on which the approximation method is applied.

## Example

`script inertiaTS {    input y = close;    input n = 20;    def x = x + 1;    def a = (n * Sum(x * y, n) - Sum(x, n) * Sum(y, n) ) / ( n * Sum(Sqr(x), n) - Sqr(Sum(x, n)));    def b = (Sum(Sqr(x), n) * Sum(y, n) - Sum(x, n) * Sum(x * y, n) ) / ( n * Sum(Sqr(x), n) - Sqr(Sum(x, n)));    plot InertiaTS = a * x + b;}input length = 20;plot LinReg1 = Inertia(close, length);plot LinReg2 = InertiaTS(close, length);`

Draws the linear regression plot for the `close` value for the defined set of bars.