condition mean min max ZT0-3 8.0889 8.0889 8.0889 ZT4-7 5.522985 5.522985 5.522985 ZT8-11 6.7909299999999995 6.7909299999999995 6.7909299999999995 ZT12-15 7.568335 7.568335 7.568335 ZT16-19 11.60775 11.60775 11.60775 ZT20-23 9.142465 9.142465 9.142465