condition mean min max ZT0-3 2.896435 1.812435 3.980435 ZT4-7 6.0125 6.0125 6.0125 ZT8-11 6.797695 6.797695 6.797695 ZT12-15 0 0 0 ZT16-19 12.913499999999999 12.913499999999999 12.913499999999999 ZT20-23 7.075595 7.075595 7.075595