condition mean min max ZT0-3 4.253378333333334 2.880505 5.003830000000001 ZT4-7 1.61173 1.61173 1.61173 ZT8-11 2.15472 2.15472 2.15472 ZT12-15 5.7507975 5.280335 6.22126 ZT16-19 6.436895 6.436895 6.436895 ZT20-23 7.41547 7.41547 7.41547