condition mean min max ZT0-3 20.205854 20.205854 20.205854 ZT4-7 23.039081000000003 23.039081000000003 23.039081000000003 ZT8-11 17.0494165 17.0494165 17.0494165 ZT12-15 17.6843925 17.6843925 17.6843925 ZT16-19 18.122736 18.122736 18.122736 ZT20-23 16.467191 16.467191 16.467191