condition mean min max ZT0-3 2.7476849999999997 2.7476849999999997 2.7476849999999997 ZT4-7 2.08689 2.08689 2.08689 ZT8-11 2.5173449999999997 2.5173449999999997 2.5173449999999997 ZT12-15 3.117035 3.117035 3.117035 ZT16-19 3.6110949999999997 3.6110949999999997 3.6110949999999997 ZT20-23 3.49467 3.49467 3.49467