condition mean min max ZT0-3 3.2366900000000003 2.924175 3.549205 ZT4-7 2.78697 2.78697 2.78697 ZT8-11 2.911365 2.911365 2.911365 ZT12-15 0 0 0 ZT16-19 4.292375 4.292375 4.292375 ZT20-23 4.37087 4.37087 4.37087