condition mean min max ZT0-3 4.16112 4.16112 4.16112 ZT4-7 2.5082500000000003 2.5082500000000003 2.5082500000000003 ZT8-11 3.8656250000000005 3.8656250000000005 3.8656250000000005 ZT12-15 11.37105 11.37105 11.37105 ZT16-19 9.337863333333333 9.337863333333333 9.337863333333333 ZT20-23 4.44416 4.44416 4.44416