condition mean min max ZT0-3 1.506895 1.506895 1.506895 ZT4-7 4.02346 4.02346 4.02346 ZT8-11 1.544855 1.544855 1.544855 ZT12-15 0.8427439999999999 0.8427439999999999 0.8427439999999999 ZT16-19 2.144557 2.144557 2.144557 ZT20-23 1.081362 1.081362 1.081362