condition mean min max ZT0-3 6.725555555666666 6.725555555666666 6.725555555666666 ZT4-7 6.411111111 6.411111111 6.411111111 ZT8-11 6.188888889 6.188888889 6.188888889 ZT12-15 5.0711111110000004 5.0711111110000004 5.0711111110000004 ZT16-19 5.057777778 5.057777778 5.057777778 ZT20-23 4.720000000000001 4.720000000000001 4.720000000000001