condition mean min max ZT0-3 1.960235 1.960235 1.960235 ZT4-7 1.367795 1.367795 1.367795 ZT8-11 1.9562599999999999 1.9562599999999999 1.9562599999999999 ZT12-15 2.67455 2.67455 2.67455 ZT16-19 4.4938400000000005 4.4938400000000005 4.4938400000000005 ZT20-23 2.918875 2.918875 2.918875