condition mean min max ZT0-3 2.981573333333333 2.82606 3.1251949999999997 ZT4-7 6.1899999999999995 6.1899999999999995 6.1899999999999995 ZT8-11 5.36079 5.36079 5.36079 ZT12-15 3.2196325 2.0812049999999997 4.35806 ZT16-19 5.723879999999999 5.723879999999999 5.723879999999999 ZT20-23 4.504185 4.504185 4.504185