condition mean min max ZT0-3 2.9190966666666665 2.628525 3.35451 ZT4-7 2.17339 2.17339 2.17339 ZT8-11 1.67753 1.67753 1.67753 ZT12-15 4.826510000000001 4.732945 4.920075000000001 ZT16-19 3.908875 3.908875 3.908875 ZT20-23 3.44074 3.44074 3.44074