## Approximating a linear regression

Given a list of points, we can estimate the best fit line using a handy library, `Statistics.LinearRegression`.

It computes the least square difference between points to estimate the best fit line. An example of a linear regression of points can be seen in the following figure:

A best-fit line is drawn through five points using linear regression

Install the appropriate library using cabal as follows:

```\$ cabal install statistics-linreg
```

### How to do it…

1. Import the following packages:

```import Statistics.LinearRegression
import qualified Data.Vector.Unboxed as U```
2. Create a series of points from their coordinates, and feed it to the `linearRegression` function, as shown in the following code snippet:

```main = do
let xs =
U.fromList [1.0, 2.0, 3.0, 4.0, 5.0] :: U.Vector Double
let ys =
U.fromList [1.0, 2.0, 1.3, 3.75, 2.25]::U.Vector Double

let (b, m) = linearRegression xs ys

print \$ concat ["y = ", show m, " x + ", show b]```
3. The resulting linear equation...