condition mean min max ZT0-3 2.10621423375 1.051831358 3.1605971095 ZT4-7 9.465058218749999 6.4475978325 12.482518605 ZT8-11 13.970799685 12.710907384999999 15.230691985 ZT12-15 6.93487583175 4.0848579175 9.784893746 ZT16-19 3.47019902725 2.7886865675 4.151711487 ZT20-23 2.66723861425 2.4823233995000002 2.8521538289999997