condition mean min max ZT0-3 425.379556 425.379556 425.379556 ZT4-7 451.34744150000006 451.34744150000006 451.34744150000006 ZT8-11 375.419381 375.419381 375.419381 ZT12-15 334.8047305 334.8047305 334.8047305 ZT16-19 279.49363700000004 279.49363700000004 279.49363700000004 ZT20-23 205.912108 205.912108 205.912108