condition mean min max ZT0-3 6.500922500000001 6.448180000000001 6.5536650000000005 ZT4-7 6.71463 6.71463 6.71463 ZT8-11 6.905725 6.905725 6.905725 ZT12-15 0 0 0 ZT16-19 8.276735 8.276735 8.276735 ZT20-23 6.911300000000001 6.911300000000001 6.911300000000001