condition mean min max ZT0-3 8.474197 8.474197 8.474197 ZT4-7 8.6438125 8.6438125 8.6438125 ZT8-11 14.173085 14.173085 14.173085 ZT12-15 8.8392115 8.8392115 8.8392115 ZT16-19 8.875408499999999 8.875408499999999 8.875408499999999 ZT20-23 9.326944999999998 9.326944999999998 9.326944999999998