condition mean min max ZT0-3 5.6363875 4.868625 6.40415 ZT4-7 9.396185 9.396185 9.396185 ZT8-11 23.73305 23.73305 23.73305 ZT12-15 0 0 0 ZT16-19 7.5236350000000005 7.5236350000000005 7.5236350000000005 ZT20-23 9.072795 9.072795 9.072795