condition mean min max ZT0-3 2.6407283333333336 2.454105 3.001115 ZT4-7 1.693205 1.693205 1.693205 ZT8-11 1.735055 1.735055 1.735055 ZT12-15 3.7053100000000003 2.4851900000000002 4.92543 ZT16-19 2.6604349999999997 2.6604349999999997 2.6604349999999997 ZT20-23 2.592035 2.592035 2.592035