This is an NPM module that allows you to perform the Mann-Whitney U test on numeric samples. The Mann-Whitney U test is a nonparametric statistical test that does not assume a normal distribution.

To use it, simply install via NPM and include it in your project file.

	var mwu = require('mann-whitney-utest');

Then, to test an array of samples, use the test method.

	var samples = [ [30, 14, 6], [12, 15, 16] ];
	console.log(mwu.test(samples)); // [ 4, 5 ]

To test whether the result is significant, use the significant method. This tests the U-value against an approximate critical value.

	var u = mwu.test(samples);
	if (mwu.significant(u, samples)) {
		console.log('The data is significant!');
	} else {
		console.log('The data is not significant.');
	}

You can check your answers using the check method. This exploits a property of the Mann-Whitney test that ensures the sum of the U values does not exceed the product of the number of observations.

	var u = mwu.test(samples);
	if (mwu.check(u, samples)) {
		console.log('The values are correct');
	}