condition mean min max ZT0-3 9.168894 9.168894 9.168894 ZT4-7 9.9631375 9.9631375 9.9631375 ZT8-11 8.9364095 8.9364095 8.9364095 ZT12-15 9.0373945 9.0373945 9.0373945 ZT16-19 8.467287 8.467287 8.467287 ZT20-23 10.1370535 10.1370535 10.1370535