Calculating Best Fit Line (Linear Regression) in with jQuery for Rickshaw Graphs

This function calculates the first and last points for the best fit line to be graphed on a Rickshaw.js chart.
We assume the points parameter is of the form [ { x: x1, y:y1}, {x:x2, y:y2}, ... ] .

function calculate_best_fit(points)

{

    // just in case

    if(points.length < 1){ 

        return [{x:0,y:0}];

    }

    

    // calculate sums

    var sum_x=0, sum_y=0, sum_xy=0, sum_xx=0, n=0, min_x=false, max_x=false;

    $.each(points, function(i, p){

            n++;

        sum_x += p.x;

        sum_y += p.y;

        sum_xy += p.x*p.y;

        sum_xx += p.x*p.x;

        min_x = (min_x === false || min_x > p.x) ? p.x : min_x;

        max_x = (max_x === false || max_x < p.x) ? p.x : max_x;

    });

    

    //calculate regression points

    var m = (sum_xy - sum_x * sum_y / n) / (sum_xx - sum_x * sum_x / n);

    b = (sum_y - m * sum_x) / n;

    y1 = b + m * min_x;

    y2 = b + m * max_x;

    console.log([ {x:min_x, y:y1}, {x:max_x, y:y2} ]);

    return [ {x:min_x, y:y1}, {x:max_x, y:y2} ];  

}

Here is the Rickshaw Graph code

    var points = [{x:1,y:3},{x:9,y:1},{x:4,y:4},{x:2,y:8}];

    var best_fit = calculate_best_fit(points);

    var chart = new Rickshaw.Graph( {

    element: document.querySelector("#chart"),

    width: 450,

    height: 280,

    renderer: 'line',

    interpolation: 'basis',

    series: [ 

        {

            name: "Linear Regression",

            color: 'red',

            data: best_fit

        },

        {

            name: "Data",

            color: 'steelblue',

            data: points

        }

    ]

} );