condition mean min max ZT0-3 8.663005 4.028105 12.9451 ZT4-7 3.141895 3.141895 3.141895 ZT8-11 1.324595 1.324595 1.324595 ZT12-15 4.3775475 3.3302300000000002 5.4248650000000005 ZT16-19 3.4775799999999997 3.4775799999999997 3.4775799999999997 ZT20-23 4.96616 4.96616 4.96616