condition mean min max ZT0-3 2.200165 2.200165 2.200165 ZT4-7 1.840675 1.840675 1.840675 ZT8-11 2.12482 2.12482 2.12482 ZT12-15 3.06231 3.06231 3.06231 ZT16-19 5.216495 5.216495 5.216495 ZT20-23 3.39813 3.39813 3.39813