condition mean min max ZT0-3 7.21075 7.21075 7.21075 ZT4-7 4.6945 4.6945 4.6945 ZT8-11 3.6336649999999997 3.6336649999999997 3.6336649999999997 ZT12-15 2.464945 2.464945 2.464945 ZT16-19 6.091325 6.091325 6.091325 ZT20-23 6.30862 6.30862 6.30862