condition mean min max ZT0-3 0.8467881666666667 0.600008 1.04882 ZT4-7 1.84415 1.84415 1.84415 ZT8-11 0.3332695 0.3332695 0.3332695 ZT12-15 1.143446 0.503057 1.7838349999999998 ZT16-19 0.7299035 0.7299035 0.7299035 ZT20-23 0.360812 0.360812 0.360812