simple-statistics/src/linear_regression_line.js

Simple Statistics

/**
 * Given the output of `linearRegression`: an object
 * with `m` and `b` values indicating slope and intercept,
 * respectively, generate a line function that translates
 * x values into y values.
 *
 * @param {Object} mb object with `m` and `b` members, representing
 * slope and intersect of desired line
 * @returns {Function} method that computes y-value at any given
 * x-value on the line.
 * @example
 * var l = linearRegressionLine(linearRegression([[0, 0], [1, 1]]));
 * l(0) // = 0
 * l(2) // = 2
 * linearRegressionLine({ b: 0, m: 1 })(1); // => 1
 * linearRegressionLine({ b: 1, m: 1 })(1); // => 2
 */
function linearRegressionLine(mb /*: { b: number, m: number }*/) {
    // Return a function that computes a `y` value for each
    // x value it is given, based on the values of `b` and `a`
    // that we just computed.
    return function (x) {
        return mb.b + mb.m * x;
    };
}

export default linearRegressionLine;