condition mean min max ZT0-3 15.925235 15.925235 15.925235 ZT4-7 15.6342695 15.6342695 15.6342695 ZT8-11 16.004057500000002 16.004057500000002 16.004057500000002 ZT12-15 14.9131775 14.9131775 14.9131775 ZT16-19 16.1153785 16.1153785 16.1153785 ZT20-23 17.1828185 17.1828185 17.1828185