condition mean min max ZT0-3 1.3247336666666667 0.643752 2.2762450000000003 ZT4-7 0.5527805 0.5527805 0.5527805 ZT8-11 1.1994315 1.1994315 1.1994315 ZT12-15 6.4907975 2.388135 10.59346 ZT16-19 3.010505 3.010505 3.010505 ZT20-23 2.44165 2.44165 2.44165