condition mean min max ZT0-3 13.570866 13.570866 13.570866 ZT4-7 15.5493205 15.5493205 15.5493205 ZT8-11 14.308988500000002 14.308988500000002 14.308988500000002 ZT12-15 13.8061895 13.8061895 13.8061895 ZT16-19 12.824723 12.824723 12.824723 ZT20-23 13.1969085 13.1969085 13.1969085