code: function() {
  			// Get the mean
  			var mean = this.mean();
  
  			// Get a new stats object to work with
  			var nums = this.clone();
  
  			// Map each element of nums to the square of the element minus the
  			// mean
  			nums.map(function(num) {
  				return Math.pow(num - mean, 2);
  			});
  
  			// Return the standard deviation
  			return Math.sqrt(nums.sum() / (nums.size() - 1));
  		}
docs: Finds the standard deviation of the numbers.  Returns the standard deviation.