condition mean min max ZT0-3 1.521685 1.521685 1.521685 ZT4-7 0.8573459999999999 0.8573459999999999 0.8573459999999999 ZT8-11 1.6511149999999999 1.6511149999999999 1.6511149999999999 ZT12-15 1.744505 1.744505 1.744505 ZT16-19 2.73085 2.73085 2.73085 ZT20-23 2.100865 2.100865 2.100865