condition mean min max ZT0-3 21.326217 21.326217 21.326217 ZT4-7 20.5208445 20.5208445 20.5208445 ZT8-11 29.240949999999998 29.240949999999998 29.240949999999998 ZT12-15 37.2905795 37.2905795 37.2905795 ZT16-19 35.652316 35.652316 35.652316 ZT20-23 32.477211499999996 32.477211499999996 32.477211499999996