condition mean min max ZT0-3 6.7750925 5.52294 8.027245 ZT4-7 3.600525 3.600525 3.600525 ZT8-11 3.1310849999999997 3.1310849999999997 3.1310849999999997 ZT12-15 0 0 0 ZT16-19 2.8842 2.8842 2.8842 ZT20-23 4.369625 4.369625 4.369625