condition mean min max ZT0-3 2.55981 2.55981 2.55981 ZT4-7 1.32697 1.32697 1.32697 ZT8-11 1.247585 1.247585 1.247585 ZT12-15 1.517655 1.517655 1.517655 ZT16-19 3.394475 3.394475 3.394475 ZT20-23 2.77198 2.77198 2.77198