condition mean min max ZT0-3 8.27989 8.27989 8.27989 ZT4-7 8.444628 8.444628 8.444628 ZT8-11 8.5234015 8.5234015 8.5234015 ZT12-15 8.648204 8.648204 8.648204 ZT16-19 7.336043999999999 7.336043999999999 7.336043999999999 ZT20-23 9.083799500000001 9.083799500000001 9.083799500000001