condition mean min max ZT0-3 2.007881073 1.953694579 2.0620675669999997 ZT4-7 2.8375567185 2.454140924 3.2209725130000004 ZT8-11 4.481790595500001 4.452107246500001 4.5114739445000005 ZT12-15 2.18752765225 1.336596739 3.0384585655 ZT16-19 2.274042317 1.9456952075 2.6023894265 ZT20-23 3.1910392625 3.1013845015 3.2806940234999997