condition mean min max ZT0-3 1.882205 1.233855 2.530555 ZT4-7 13.9479 13.9479 13.9479 ZT8-11 17.929585 17.929585 17.929585 ZT12-15 0 0 0 ZT16-19 2.485805 2.485805 2.485805 ZT20-23 8.737385 8.737385 8.737385