condition mean min max ZT0-3 3.1924900000000003 3.1924900000000003 3.1924900000000003 ZT4-7 2.247025 2.247025 2.247025 ZT8-11 3.8578449999999997 3.8578449999999997 3.8578449999999997 ZT12-15 4.611935 4.611935 4.611935 ZT16-19 5.091415 5.091415 5.091415 ZT20-23 3.308295 3.308295 3.308295