condition mean min max ZT0-3 8.782575 8.782575 8.782575 ZT4-7 9.1139765 9.1139765 9.1139765 ZT8-11 9.2083135 9.2083135 9.2083135 ZT12-15 8.127564 8.127564 8.127564 ZT16-19 8.500430999999999 8.500430999999999 8.500430999999999 ZT20-23 9.687977 9.687977 9.687977