gistfile1.js

'use strict';
var uuid = require('node-uuid'),
	_ = require('lodash');

var runCount = 1000000,
	time = process.hrtime(),
	inc = -1,
	resultsArr = [],
	uniqueArr = [],
	truths = 0,
	segment = { high: 50, low: 30 };

console.log('target population: ', ((segment.high - segment.low) / 100));

while (++inc < runCount) {
	var id = uuid.v4(),
		chars = parseChars(id),
		mod = modSegment(chars, segment);

	if (mod.inSegment) {
		truths++;
	}

	resultsArr.push(mod);
	uniqueArr.push(id);

}

var percentTrue = truths / runCount;
console.info('percent inSegment true: ', percentTrue);
console.info('all unique?', (_.uniq(uniqueArr).length === runCount));
var diff = process.hrtime(time);
console.info("Execution time (hr): %ds %dms", diff[0], diff[1]/1000000);


/* Convert letters to their char code in the uuid string */
function parseChars(uuid) {
	var code = [],
		a = 0;
	while (a < uuid.length) {
		isNaN(uuid[a]) ? code.push(uuid.charCodeAt(a)) : code.push(uuid[a]);
		a++;
	}
	return code.join('');
}

/* Find the modulus the uuid modified string lives within and it's segment */
function modSegment(num, segment) {
	var cookieMod = (num / 2) % 100;
	return {
		cookieMod: cookieMod,
		inSegment: (cookieMod <= segment.high) && (cookieMod >= segment.low)
	}
}