condition mean min max ZT0-3 4.5629124999999995 1.571605 7.554219999999999 ZT4-7 2.094549 2.094549 2.094549 ZT8-11 0.5795035 0.5795035 0.5795035 ZT12-15 0 0 0 ZT16-19 21.76785 21.76785 21.76785 ZT20-23 2.784195 2.784195 2.784195