condition mean min max ZT0-3 203.668677 203.668677 203.668677 ZT4-7 252.216913 252.216913 252.216913 ZT8-11 259.631357 259.631357 259.631357 ZT12-15 320.4990805 320.4990805 320.4990805 ZT16-19 196.86718150000002 196.86718150000002 196.86718150000002 ZT20-23 165.619458 165.619458 165.619458