condition mean min max ZT0-3 17.499246 17.499246 17.499246 ZT4-7 10.6917065 10.6917065 10.6917065 ZT8-11 8.1889795 8.1889795 8.1889795 ZT12-15 9.842845 9.842845 9.842845 ZT16-19 7.5687305 7.5687305 7.5687305 ZT20-23 9.0404015 9.0404015 9.0404015