condition mean min max ZT0-3 2.440595 2.25898 2.62221 ZT4-7 4.225215 4.225215 4.225215 ZT8-11 2.77571 2.77571 2.77571 ZT12-15 0 0 0 ZT16-19 3.349995 3.349995 3.349995 ZT20-23 3.657325 3.657325 3.657325