condition mean min max ZT0-3 18.793833333333332 17.814999999999998 19.31755 ZT4-7 6.24865 6.24865 6.24865 ZT8-11 3.099555 3.099555 3.099555 ZT12-15 9.93533 9.711365 10.159295 ZT16-19 9.267345 9.267345 9.267345 ZT20-23 11.84875 11.84875 11.84875