condition mean min max ZT0-3 19.299999999999997 19.299999999999997 19.299999999999997 ZT4-7 41.0 41.0 41.0 ZT8-11 58.9 58.9 58.9 ZT12-15 23.6 23.6 23.6 ZT16-19 27.700000000000003 27.700000000000003 27.700000000000003 ZT20-23 30.7 30.7 30.7