condition mean min max ZT0-3 20.124886 20.124886 20.124886 ZT4-7 21.447424 21.447424 21.447424 ZT8-11 13.557193999999999 13.557193999999999 13.557193999999999 ZT12-15 19.442352500000002 19.442352500000002 19.442352500000002 ZT16-19 9.4610705 9.4610705 9.4610705 ZT20-23 10.0867145 10.0867145 10.0867145