condition mean min max ZT0-3 3.182805 3.182805 3.182805 ZT4-7 0.8753555 0.8753555 0.8753555 ZT8-11 1.8219599999999998 1.8219599999999998 1.8219599999999998 ZT12-15 3.0304 3.0304 3.0304 ZT16-19 3.4748099999999997 3.4748099999999997 3.4748099999999997 ZT20-23 3.715445 3.715445 3.715445