condition mean min max ZT0-3 3.128860833333333 2.9310324999999997 3.37364 ZT4-7 1.23884 1.23884 1.23884 ZT8-11 1.551611 1.551611 1.551611 ZT12-15 2.9349675 1.455035 4.414899999999999 ZT16-19 4.181055000000001 4.181055000000001 4.181055000000001 ZT20-23 5.68069 5.68069 5.68069