condition mean min max ZT0-3 27.049999999999997 27.049999999999997 27.049999999999997 ZT4-7 16.7 16.7 16.7 ZT8-11 39.2 39.2 39.2 ZT12-15 21.700000000000003 21.700000000000003 21.700000000000003 ZT16-19 23.5 23.5 23.5 ZT20-23 20.299999999999997 20.299999999999997 20.299999999999997