condition mean min max ZT0-3 3.74752 3.74752 3.74752 ZT4-7 2.867825 2.867825 2.867825 ZT8-11 5.5132650000000005 5.5132650000000005 5.5132650000000005 ZT12-15 7.3177900000000005 7.3177900000000005 7.3177900000000005 ZT16-19 6.83539 6.83539 6.83539 ZT20-23 5.015735 5.015735 5.015735