condition mean min max ZT0-3 1.5269280166666666 0.69786205 2.1255699999999997 ZT4-7 0.4349525 0.4349525 0.4349525 ZT8-11 0.934867 0.934867 0.934867 ZT12-15 1.09321575 0.9568645 1.2295669999999999 ZT16-19 0.888209 0.888209 0.888209 ZT20-23 1.045675 1.045675 1.045675