condition mean min max ZT0-3 8.585363333333333 4.2915600000000005 11.803 ZT4-7 2.40252 2.40252 2.40252 ZT8-11 4.8019300000000005 4.8019300000000005 4.8019300000000005 ZT12-15 5.768319999999999 5.337675 6.198964999999999 ZT16-19 12.767199999999999 12.767199999999999 12.767199999999999 ZT20-23 17.41835 17.41835 17.41835