Distribution Probability

gistfile1.js

function randomProb(hash, n){
	var bucketHash = {}, bucketHash, index, key, 
	sum=0, results =[], randValue, curBucketValue;

	for(key in hash){
		sum += hash[key]; 
		bucketHash[key] =  sum; 
	}
	for (var index = 0; index < n; index++) {
		randValue = Math.random(); 
		for(key in bucketHash){
			curBucketValue = bucketHash[key];
			if(curBucketValue>randValue){
				results.push(key); 
				break; 
			}
		}
	};
	return results; 
}


var hash  = { 1 : 0.5 , 2 : 0.5};
console.log('%j', randomProb(hash, 4));