condition mean min max ZT0-3 20.158065 20.158065 20.158065 ZT4-7 25.273180500000002 25.273180500000002 25.273180500000002 ZT8-11 23.072941 23.072941 23.072941 ZT12-15 21.032705999999997 21.032705999999997 21.032705999999997 ZT16-19 18.826614 18.826614 18.826614 ZT20-23 19.078393 19.078393 19.078393