Spearman Rank Correlation Index

gistfile1.txt

function getSpearmanRankCorrelation(list_x, list_y) {

	var n;

	if (list_x.length !== list_y.length)
	throw "Error: Lists are of different length";
	else n = list_x.length;

	sorted_x = list_x.sort();
	sorted_y = list_y.sort();

	var summation = 0;

	for (var i = 0; i < n; i++) {
		summation += Math.pow((sorted_x[i][1] - sorted_y[i][1]), 2);
	}

	var index = 1 - ((6 * summation) / (n * (Math.pow(n, 2) - 1)));

	return index;

};