condition mean min max ZT0-3 10.279585 10.279585 10.279585 ZT4-7 9.234995 9.234995 9.234995 ZT8-11 6.058625 6.058625 6.058625 ZT12-15 6.474825 6.474825 6.474825 ZT16-19 11.8979 11.8979 11.8979 ZT20-23 9.485225 9.485225 9.485225