condition mean min max ZT0-3 3.810096833333333 1.0122555 5.331049999999999 ZT4-7 1.1420775 1.1420775 1.1420775 ZT8-11 2.330165 2.330165 2.330165 ZT12-15 2.8545100000000003 2.047685 3.6613350000000002 ZT16-19 1.2883749999999998 1.2883749999999998 1.2883749999999998 ZT20-23 4.996265 4.996265 4.996265