condition mean min max ZT0-3 3.170131666666667 2.644875 4.1133 ZT4-7 6.787845 6.787845 6.787845 ZT8-11 10.236715 10.236715 10.236715 ZT12-15 6.340485 6.32962 6.35135 ZT16-19 8.195865000000001 8.195865000000001 8.195865000000001 ZT20-23 7.22039 7.22039 7.22039