condition mean min max ZT0-3 11.60785 11.60785 11.60785 ZT4-7 14.87865 14.87865 14.87865 ZT8-11 12.52595 12.52595 12.52595 ZT12-15 9.65135 9.65135 9.65135 ZT16-19 8.86483 8.86483 8.86483 ZT20-23 8.61376 8.61376 8.61376