condition mean min max ZT0-3 8.096825 7.752945 8.440705000000001 ZT4-7 7.185945 7.185945 7.185945 ZT8-11 7.5762350000000005 7.5762350000000005 7.5762350000000005 ZT12-15 0 0 0 ZT16-19 9.27674 9.27674 9.27674 ZT20-23 9.409125 9.409125 9.409125