condition mean min max ZT0-3 2.2312933015 2.091046681 2.3715399219999997 ZT4-7 1.5859083795 1.2551916804999999 1.9166250785 ZT8-11 2.1022439635 1.7879761205 2.4165118065 ZT12-15 3.15135764575 2.3686829585 3.934032333 ZT16-19 3.1444351087499998 2.669995575 3.6188746425 ZT20-23 7.1710501865000005 6.5489894895 7.793110883500001