condition mean min max ZT0-3 3.4565475 3.16979 3.7433050000000003 ZT4-7 4.08869 4.08869 4.08869 ZT8-11 3.928915 3.928915 3.928915 ZT12-15 0 0 0 ZT16-19 6.897505000000001 6.897505000000001 6.897505000000001 ZT20-23 8.457955 8.457955 8.457955