condition mean min max ZT0-3 15.751404 15.751404 15.751404 ZT4-7 14.7241425 14.7241425 14.7241425 ZT8-11 13.2014055 13.2014055 13.2014055 ZT12-15 16.2022915 16.2022915 16.2022915 ZT16-19 14.9045525 14.9045525 14.9045525 ZT20-23 17.4086625 17.4086625 17.4086625