condition mean min max ZT0-3 1.84996 1.84996 1.84996 ZT4-7 1.9238899999999999 1.9238899999999999 1.9238899999999999 ZT8-11 4.8318650000000005 4.8318650000000005 4.8318650000000005 ZT12-15 3.5231500000000002 3.5231500000000002 3.5231500000000002 ZT16-19 3.7419133333333336 3.7419133333333336 3.7419133333333336 ZT20-23 3.3107 3.3107 3.3107