condition mean min max ZT0-3 2.3236955000000004 2.3236955000000004 2.3236955000000004 ZT4-7 4.475015 4.475015 4.475015 ZT8-11 2.55831 2.55831 2.55831 ZT12-15 3.407235 3.407235 3.407235 ZT16-19 3.913945 3.913945 3.913945 ZT20-23 3.0988100000000003 3.0988100000000003 3.0988100000000003