Gaussian normal distribution

normal-rand.js

/**
 * Generate a random number considering gaussian normal distribution.
 *
 * @param min
 *   The minimal value. Can be negative or positive.
 *
 * @param max
 *   The maximal value. Should be higher then min.
 *
 * @param dis
 *   The distribution. The higher is value is, the less likely min or max will
 *   be directly returned.
 *
 * @return
 *   A random number between min and max respecting the normal distribution.
 */
function normalRand(min, max, dis) {
  var dis = typeof dis !== 'undefined' ? dis : 42;
  var o = 0;
  var delta = max - min;
  for(var i = 0; i < dis; i++) {
    o += Math.random()*delta+min
  }
  o = Math.round(o / dis);
  return o;
}