condition mean min max ZT0-3 9.92888889 9.92888889 9.92888889 ZT4-7 7.218888889 7.218888889 7.218888889 ZT8-11 6.217222222 6.217222222 6.217222222 ZT12-15 6.785555555666667 6.785555555666667 6.785555555666667 ZT16-19 7.382222222 7.382222222 7.382222222 ZT20-23 7.51 7.51 7.51