condition mean min max ZT0-3 2.2296983333333333 1.62636 2.82139 ZT4-7 2.2257249999999997 2.2257249999999997 2.2257249999999997 ZT8-11 2.54157 2.54157 2.54157 ZT12-15 3.4415025000000004 2.74316 4.139845 ZT16-19 3.649115 3.649115 3.649115 ZT20-23 6.0117650000000005 6.0117650000000005 6.0117650000000005