condition mean min max ZT0-3 2.352785 1.8628399999999998 3.226425 ZT4-7 1.8049 1.8049 1.8049 ZT8-11 1.49588 1.49588 1.49588 ZT12-15 1.39751075 1.3838499999999998 1.4111715 ZT16-19 1.98758 1.98758 1.98758 ZT20-23 2.340835 2.340835 2.340835