condition mean min max ZT0-3 1.969505 1.969505 1.969505 ZT4-7 1.4696799999999999 1.4696799999999999 1.4696799999999999 ZT8-11 1.89555 1.89555 1.89555 ZT12-15 1.947975 1.947975 1.947975 ZT16-19 2.586795 2.586795 2.586795 ZT20-23 2.199185 2.199185 2.199185