condition mean min max ZT0-3 665.666313 665.666313 665.666313 ZT4-7 203.50277599999998 203.50277599999998 203.50277599999998 ZT8-11 170.602136 170.602136 170.602136 ZT12-15 319.0652005 319.0652005 319.0652005 ZT16-19 454.5281545 454.5281545 454.5281545 ZT20-23 437.0358845 437.0358845 437.0358845