condition mean min max ZT0-3 21.601799999999997 21.601799999999997 21.601799999999997 ZT4-7 18.466700000000003 18.466700000000003 18.466700000000003 ZT8-11 17.06615 17.06615 17.06615 ZT12-15 17.4995 17.4995 17.4995 ZT16-19 18.5517 18.5517 18.5517 ZT20-23 18.91665 18.91665 18.91665