condition mean min max ZT0-3 5.171456666666667 2.70863 8.159775 ZT4-7 14.6323 14.6323 14.6323 ZT8-11 13.492799999999999 13.492799999999999 13.492799999999999 ZT12-15 16.2016225 14.372895 18.03035 ZT16-19 12.4906 12.4906 12.4906 ZT20-23 12.6683 12.6683 12.6683