condition mean min max ZT0-3 3.031144 0.538517 4.74395 ZT4-7 0.539716 0.539716 0.539716 ZT8-11 0.6483085 0.6483085 0.6483085 ZT12-15 1.8313125000000001 1.25323 2.409395 ZT16-19 3.21902 3.21902 3.21902 ZT20-23 5.069459999999999 5.069459999999999 5.069459999999999