condition mean min max ZT0-3 26.477595895 24.093401659999998 28.86179013 ZT4-7 18.68755338 16.498435975 20.876670785 ZT8-11 14.2699233125 11.894388095 16.64545853 ZT12-15 11.896393493249999 11.611082826999999 12.181704159499999 ZT16-19 19.028557454999998 17.10646591 20.950649 ZT20-23 16.97862371 15.112468615000001 18.844778804999997