condition mean min max ZT0-3 6.255765 6.255765 6.255765 ZT4-7 3.9979449999999996 3.9979449999999996 3.9979449999999996 ZT8-11 2.7953 2.7953 2.7953 ZT12-15 3.12432 3.12432 3.12432 ZT16-19 10.04055 10.04055 10.04055 ZT20-23 7.250995 7.250995 7.250995