condition mean min max ZT0-3 9.940555 9.940555 9.940555 ZT4-7 2.25162 2.25162 2.25162 ZT8-11 1.7170100000000001 1.7170100000000001 1.7170100000000001 ZT12-15 5.26839 5.26839 5.26839 ZT16-19 12.541599999999999 12.541599999999999 12.541599999999999 ZT20-23 17.5751 17.5751 17.5751