condition mean min max ZT0-3 16.388066666666667 0.0 29.4476 ZT4-7 6.2654499999999995 6.2654499999999995 6.2654499999999995 ZT8-11 12.92816 12.92816 12.92816 ZT12-15 36.577175 26.508699999999997 46.64565 ZT16-19 33.6382 33.6382 33.6382 ZT20-23 62.2839 62.2839 62.2839