condition mean min max ZT0-3 8.416664 8.416664 8.416664 ZT4-7 10.0470825 10.0470825 10.0470825 ZT8-11 8.6789245 8.6789245 8.6789245 ZT12-15 8.4482865 8.4482865 8.4482865 ZT16-19 8.2224545 8.2224545 8.2224545 ZT20-23 8.1878245 8.1878245 8.1878245