condition mean min max ZT0-3 1.6345853333333333 1.0074109999999998 2.25819 ZT4-7 0.7459495 0.7459495 0.7459495 ZT8-11 2.230175 2.230175 2.230175 ZT12-15 1.7832350000000001 1.6296750000000002 1.936795 ZT16-19 1.70959 1.70959 1.70959 ZT20-23 2.570315 2.570315 2.570315