condition mean min max ZT0-3 0.87704597 0.40091258700000004 1.3531793529999998 ZT4-7 2.67080260475 2.020367082 3.3212381275 ZT8-11 3.4334786850000003 3.3409526760000006 3.526004694 ZT12-15 2.4009011462500003 2.15400874 2.6477935525000005 ZT16-19 1.9520468524999999 1.592114487 2.311979218 ZT20-23 2.618469502 2.565943241 2.670995763