condition mean min max ZT0-3 2.2772783333333333 2.080265 2.664345 ZT4-7 2.2091250000000002 2.2091250000000002 2.2091250000000002 ZT8-11 5.16902 5.16902 5.16902 ZT12-15 8.013515 7.57355 8.45348 ZT16-19 5.497705 5.497705 5.497705 ZT20-23 4.10308 4.10308 4.10308