condition mean min max ZT0-3 13.197418333333333 10.453355 14.79715 ZT4-7 10.31301 10.31301 10.31301 ZT8-11 15.389000000000001 15.389000000000001 15.389000000000001 ZT12-15 22.482525000000003 20.8942 24.07085 ZT16-19 17.964750000000002 17.964750000000002 17.964750000000002 ZT20-23 18.36905 18.36905 18.36905