condition mean min max ZT0-3 1.84459 1.84459 1.84459 ZT4-7 1.3798 1.3798 1.3798 ZT8-11 2.574085 2.574085 2.574085 ZT12-15 1.60866 1.60866 1.60866 ZT16-19 3.33495 3.33495 3.33495 ZT20-23 2.15918 2.15918 2.15918