condition mean min max ZT0-3 7.940856666666667 4.57881 9.984005 ZT4-7 4.846865 4.846865 4.846865 ZT8-11 4.6124849999999995 4.6124849999999995 4.6124849999999995 ZT12-15 6.7407975 5.52224 7.959355 ZT16-19 7.655329999999999 7.655329999999999 7.655329999999999 ZT20-23 11.66815 11.66815 11.66815