condition mean min max ZT0-3 20.770925 20.6101 20.93175 ZT4-7 17.63015 17.63015 17.63015 ZT8-11 15.636800000000001 15.636800000000001 15.636800000000001 ZT12-15 0 0 0 ZT16-19 17.924599999999998 17.924599999999998 17.924599999999998 ZT20-23 21.88175 21.88175 21.88175