condition mean min max ZT0-3 171.847441 171.847441 171.847441 ZT4-7 67.43805 67.43805 67.43805 ZT8-11 51.5828525 51.5828525 51.5828525 ZT12-15 64.8352065 64.8352065 64.8352065 ZT16-19 129.82843400000002 129.82843400000002 129.82843400000002 ZT20-23 246.0794915 246.0794915 246.0794915