condition mean min max ZT0-3 1.9804150000000003 1.9804150000000003 1.9804150000000003 ZT4-7 0.976979 0.976979 0.976979 ZT8-11 2.06113 2.06113 2.06113 ZT12-15 2.083785 2.083785 2.083785 ZT16-19 3.145225 3.145225 3.145225 ZT20-23 1.429975 1.429975 1.429975