condition mean min max ZT0-3 5.1350625 4.7371 5.533025 ZT4-7 4.529675 4.529675 4.529675 ZT8-11 17.71835 17.71835 17.71835 ZT12-15 0 0 0 ZT16-19 19.263550000000002 19.263550000000002 19.263550000000002 ZT20-23 12.8516 12.8516 12.8516