condition mean min max ZT0-3 19.71225 18.5837 20.8408 ZT4-7 19.6522 19.6522 19.6522 ZT8-11 20.36145 20.36145 20.36145 ZT12-15 0 0 0 ZT16-19 34.8305 34.8305 34.8305 ZT20-23 33.5635 33.5635 33.5635