condition mean min max ZT0-3 9.001961244 8.186966235 9.816956252999999 ZT4-7 7.287740985 7.1902186135 7.3852633565 ZT8-11 8.53706391575 7.814951154000001 9.259176677500001 ZT12-15 11.5149650165 9.799726843 13.230203190000001 ZT16-19 17.506040945 14.75834433 20.253737559999998 ZT20-23 33.8647305475 26.271414585000002 41.45804651