condition mean min max ZT0-3 5.315826666666666 5.315826666666666 5.315826666666666 ZT4-7 3.6024149999999997 3.6024149999999997 3.6024149999999997 ZT8-11 2.74593 2.74593 2.74593 ZT12-15 2.86753 2.86753 2.86753 ZT16-19 5.9477400000000005 5.9477400000000005 5.9477400000000005 ZT20-23 4.66929 4.66929 4.66929