code: def mean_moving_time(self, data_frame):
          
          diff = data_frame.td[1:-1].values-data_frame.td[0:-2].values
          mmt = np.mean(diff[np.arange(1,len(diff),2)]) * 1000.0
          duration = math.ceil(data_frame.td[-1])
  
          return mmt, duration
docs: This method calculates the mean time (ms) that the hand was moving from one target to the next
  
              :param data_frame: the data frame
              :type data_frame: pandas.DataFrame
              :return mmt: the mean moving time in ms
              :rtype mmt: float