condition mean min max ZT0-3 11.654638333333333 11.400965 11.962 ZT4-7 8.996475 8.996475 8.996475 ZT8-11 8.885355 8.885355 8.885355 ZT12-15 7.524122499999999 7.424869999999999 7.623374999999999 ZT16-19 8.25375 8.25375 8.25375 ZT20-23 14.56645 14.56645 14.56645