code: function sum_nth_power_deviations(x, n) {
          var mean_value = mean(x),
              sum = 0;
  
          for (var i = 0; i < x.length; i++) {
              sum += Math.pow(x[i] - mean_value, n);
          }
  
          return sum;
      }
docs: The sum of deviations to the Nth power. When n=2 it's the sum of squared deviations. When n=3 it's the sum of cubed deviations.  depends on `mean()`