condition mean min max ZT0-3 5.855565 5.855565 5.855565 ZT4-7 4.35818 4.35818 4.35818 ZT8-11 4.580955 4.580955 4.580955 ZT12-15 4.691375 4.691375 4.691375 ZT16-19 6.528915 6.528915 6.528915 ZT20-23 6.55276 6.55276 6.55276