condition mean min max ZT0-3 1.9101833333333333 1.194575 3.076465 ZT4-7 2.5407450000000003 2.5407450000000003 2.5407450000000003 ZT8-11 1.73933 1.73933 1.73933 ZT12-15 3.9129449999999997 3.7416549999999997 4.084235 ZT16-19 4.11968 4.11968 4.11968 ZT20-23 4.33695 4.33695 4.33695