condition mean min max ZT0-3 8.446746 8.446746 8.446746 ZT4-7 7.938760500000001 7.938760500000001 7.938760500000001 ZT8-11 8.132735499999999 8.132735499999999 8.132735499999999 ZT12-15 7.4826125 7.4826125 7.4826125 ZT16-19 7.946894 7.946894 7.946894 ZT20-23 7.4601275000000005 7.4601275000000005 7.4601275000000005