condition mean min max ZT0-3 3.6379175000000004 3.11382 4.162015 ZT4-7 3.385935 3.385935 3.385935 ZT8-11 3.9666050000000004 3.9666050000000004 3.9666050000000004 ZT12-15 0 0 0 ZT16-19 5.363275 5.363275 5.363275 ZT20-23 6.6359449999999995 6.6359449999999995 6.6359449999999995