code: function stat(fn, n) {
  	var n2 = n,
  		times = [],
  		sum = 0,
  		t, avg, median
  	while (n2--) {
  		t = fn()
  		sum += t
  		times.push(t)
  	}
  	avg = sum / n
  	times.sort(function (a, b) {
  		return a - b
  	})
  	median = times[Math.floor(times.length / 2)]
  	if (times.length % 2 === 0) {
  		median = (median + times[times.length / 2 - 1]) / 2
  	}
  	return {
  		avg: avg,
  		median: median
  	}
  }
docs: Make a statistical experiment on fn
  @param {Function} fn A function that receives nothing and returns a number
  @param {number} n Number of probes to takes
  @returns {{avg: number, median: number}}