condition mean min max ZT0-3 10.633899 10.633899 10.633899 ZT4-7 8.962501 8.962501 8.962501 ZT8-11 9.200031 9.200031 9.200031 ZT12-15 9.5380185 9.5380185 9.5380185 ZT16-19 9.1006195 9.1006195 9.1006195 ZT20-23 9.9828385 9.9828385 9.9828385