condition mean min max ZT0-3 2.1437999999999997 2.1437999999999997 2.1437999999999997 ZT4-7 1.186825 1.186825 1.186825 ZT8-11 2.55361 2.55361 2.55361 ZT12-15 3.010975 3.010975 3.010975 ZT16-19 4.448565 4.448565 4.448565 ZT20-23 2.932645 2.932645 2.932645