condition mean min max ZT0-3 1.1920735 0.6455095 1.77778 ZT4-7 0.9562854999999999 0.9562854999999999 0.9562854999999999 ZT8-11 2.737435 2.737435 2.737435 ZT12-15 2.4216375 1.71685 3.1264250000000002 ZT16-19 2.90522 2.90522 2.90522 ZT20-23 3.04089 3.04089 3.04089