Linear Regression experiment

calculate-linear-regression.js

//const data = [1.5, 3.8, 6.7, 9.0, 11.2, 13.6, 16]
const data = [4, 4, 3, 5, 4, 3, 2, 2, 3, 4, 1, 1, 3]

const x = data.map((_, i) => i + 1)
const y = data
const xy = data.map((value, i) => (i + 1) * value)

const xPow2 = data.map((_, i) => (i + 1) ** 2)

//const sumOfX =data.reduce((acc, _, i) => acc + i
const sum = arr => arr.reduce((acc,value)=> acc + value)

// Max 
const n = x[x.length - 1] 

// Sloap
const m = ((n  * sum(xy)) - (sum(x)) * sum(y)) / ((n * sum(xPow2)) - (sum(x) ** 2))   

// 
const b = (sum(y) - (m * sum(x))) / n 


const Y = xPos => (m * xPos) + b 
document.body.insertAdjacentHTML('afterbegin', 
`
<div>x: ${x}</div>
<div>y: ${y}</div>
<div>xy: ${xy}</div>
<div>x^2: ${xPow2}</div>
<br>
<div> Σx: ${sum(x)}</div>
<div>y: ${sum(y)}</div>
<div>xy: ${sum(xy)}</div>
<div>x^2: ${sum(xPow2)}</div>
<br>
<div>m (Sloap): ${m}</div>
<div>b: ${b}</div>
<br>
Example of 2 
<div>Y: ${Y(2)}</div> 

Example of 5 
<div>Y: ${Y(5)}</div>

Example of 7 
<div>Y: ${Y(7)}</div>
`)