condition mean min max ZT0-3 3.4145783333333335 2.39648 4.02548 ZT4-7 3.5635200000000005 3.5635200000000005 3.5635200000000005 ZT8-11 2.199255 2.199255 2.199255 ZT12-15 6.70977 5.112715 8.306825 ZT16-19 6.12101 6.12101 6.12101 ZT20-23 7.602405 7.602405 7.602405