condition mean min max ZT0-3 4.876805 4.876805 4.876805 ZT4-7 3.12554 3.12554 3.12554 ZT8-11 2.055825 2.055825 2.055825 ZT12-15 1.54184 1.54184 1.54184 ZT16-19 2.2483750000000002 2.2483750000000002 2.2483750000000002 ZT20-23 6.579945 6.579945 6.579945