condition mean min max ZT0-3 2.2259816666666663 2.017245 2.4722549999999996 ZT4-7 1.326349 1.326349 1.326349 ZT8-11 1.38178 1.38178 1.38178 ZT12-15 3.9830375 3.6502250000000003 4.31585 ZT16-19 2.87697 2.87697 2.87697 ZT20-23 2.9625250000000003 2.9625250000000003 2.9625250000000003