condition mean min max ZT0-3 6.723375000000001 6.723375000000001 6.723375000000001 ZT4-7 5.4770900000000005 5.4770900000000005 5.4770900000000005 ZT8-11 4.802635 4.802635 4.802635 ZT12-15 6.30119 6.30119 6.30119 ZT16-19 6.964095 6.964095 6.964095 ZT20-23 6.824695 6.824695 6.824695