condition mean min max ZT0-3 2.3043916666666666 1.2291750000000001 3.3833 ZT4-7 1.92984 1.92984 1.92984 ZT8-11 7.344875 7.344875 7.344875 ZT12-15 5.681825 4.45758 6.90607 ZT16-19 2.9403699999999997 2.9403699999999997 2.9403699999999997 ZT20-23 3.28701 3.28701 3.28701