condition mean min max ZT0-3 8.27989 8.27989 8.27989 ZT4-7 8.9790925 8.9790925 8.9790925 ZT8-11 8.669691 8.669691 8.669691 ZT12-15 9.306535499999999 9.306535499999999 9.306535499999999 ZT16-19 8.518787 8.518787 8.518787 ZT20-23 8.205313499999999 8.205313499999999 8.205313499999999