condition mean min max ZT0-3 9.680031666666666 8.953355 10.212925 ZT4-7 8.59339 8.59339 8.59339 ZT8-11 9.576695 9.576695 9.576695 ZT12-15 15.0105 13.904499999999999 16.116500000000002 ZT16-19 13.3444 13.3444 13.3444 ZT20-23 13.88525 13.88525 13.88525