condition mean min max ZT0-3 11.366076666666666 8.25403 13.8564 ZT4-7 6.9834499999999995 6.9834499999999995 6.9834499999999995 ZT8-11 13.71235 13.71235 13.71235 ZT12-15 15.338175 15.13185 15.5445 ZT16-19 14.594149999999999 14.594149999999999 14.594149999999999 ZT20-23 18.10035 18.10035 18.10035