condition mean min max ZT0-3 11.834025 11.0973 12.57075 ZT4-7 19.35445 19.35445 19.35445 ZT8-11 18.538449999999997 18.538449999999997 18.538449999999997 ZT12-15 0 0 0 ZT16-19 14.081800000000001 14.081800000000001 14.081800000000001 ZT20-23 12.9731 12.9731 12.9731