condition mean min max ZT0-3 11.0156925 10.92465 11.106735 ZT4-7 11.9612 11.9612 11.9612 ZT8-11 20.160449999999997 20.160449999999997 20.160449999999997 ZT12-15 0 0 0 ZT16-19 18.9213 18.9213 18.9213 ZT20-23 13.06155 13.06155 13.06155