condition mean min max ZT0-3 4.218635 4.218635 4.218635 ZT4-7 3.278715 3.278715 3.278715 ZT8-11 3.361155 3.361155 3.361155 ZT12-15 4.0339100000000006 4.0339100000000006 4.0339100000000006 ZT16-19 4.86004 4.86004 4.86004 ZT20-23 4.019345 4.019345 4.019345