condition mean min max ZT0-3 351.155134 351.155134 351.155134 ZT4-7 1003.370062 1003.370062 1003.370062 ZT8-11 1512.6985445 1512.6985445 1512.6985445 ZT12-15 942.5939085 942.5939085 942.5939085 ZT16-19 772.5986795 772.5986795 772.5986795 ZT20-23 827.354492 827.354492 827.354492