condition mean min max ZT0-3 2.7261835 2.7261835 2.7261835 ZT4-7 0.9745364999999999 0.9745364999999999 0.9745364999999999 ZT8-11 0.5202025 0.5202025 0.5202025 ZT12-15 0.615753 0.615753 0.615753 ZT16-19 0.40398116666666667 0.40398116666666667 0.40398116666666667 ZT20-23 3.3966849999999997 3.3966849999999997 3.3966849999999997