condition mean min max ZT0-3 2.15954325 1.982829495 2.336257005 ZT4-7 3.2396974912500003 2.9214768285 3.557918154 ZT8-11 3.4597815514999994 2.4813431479999997 4.438219954999999 ZT12-15 14.344037269 9.2096827805 19.4783917575 ZT16-19 19.159474945 18.744177085 19.574772805000002 ZT20-23 18.2276452975 16.5388276 19.916462995