condition mean min max ZT0-3 5.788221666666667 4.513315 6.6749 ZT4-7 4.85482 4.85482 4.85482 ZT8-11 4.65186 4.65186 4.65186 ZT12-15 4.5732625 4.18544 4.961085 ZT16-19 4.103635 4.103635 4.103635 ZT20-23 5.46659 5.46659 5.46659