condition mean min max ZT0-3 17.653379 17.653379 17.653379 ZT4-7 18.1356945 18.1356945 18.1356945 ZT8-11 16.440692 16.440692 16.440692 ZT12-15 15.222435 15.222435 15.222435 ZT16-19 17.595479 17.595479 17.595479 ZT20-23 18.820872 18.820872 18.820872