condition mean min max ZT0-3 12.219265 10.61918 13.81935 ZT4-7 14.56055 14.56055 14.56055 ZT8-11 13.3397 13.3397 13.3397 ZT12-15 0 0 0 ZT16-19 21.9107 21.9107 21.9107 ZT20-23 15.8764 15.8764 15.8764