# File lib/ai4r/data/data_set.rb, line 212
      def get_mean_or_mode
        mean = []
        num_attributes.times do |i|
          mean[i] =
                  if @data_items.first[i].is_a?(Numeric)
                    Statistics.mean(self, i)
                  else
                    Statistics.mode(self, i)
                  end
        end
        return mean
      end