condition mean min max ZT0-3 3.279908333333333 2.585465 3.9002299999999996 ZT4-7 2.7091950000000002 2.7091950000000002 2.7091950000000002 ZT8-11 3.25124 3.25124 3.25124 ZT12-15 5.6321125 4.954549999999999 6.309675 ZT16-19 6.015435 6.015435 6.015435 ZT20-23 6.28713 6.28713 6.28713