condition mean min max ZT0-3 18.053016666666668 14.0789 20.91675 ZT4-7 13.6327 13.6327 13.6327 ZT8-11 12.193850000000001 12.193850000000001 12.193850000000001 ZT12-15 16.209375 16.05425 16.3645 ZT16-19 16.17795 16.17795 16.17795 ZT20-23 21.0364 21.0364 21.0364