condition mean min max ZT0-3 4.039075 4.039075 4.039075 ZT4-7 3.694655 3.694655 3.694655 ZT8-11 2.64613 2.64613 2.64613 ZT12-15 3.319165 3.319165 3.319165 ZT16-19 3.2212949999999996 3.2212949999999996 3.2212949999999996 ZT20-23 2.614885 2.614885 2.614885