condition mean min max ZT0-3 4.232950000000001 4.0133 4.4526 ZT4-7 2.624255 2.624255 2.624255 ZT8-11 3.757415 3.757415 3.757415 ZT12-15 0 0 0 ZT16-19 3.870065 3.870065 3.870065 ZT20-23 4.559865 4.559865 4.559865