condition mean min max ZT0-3 3.344003333333333 2.552875 3.82653 ZT4-7 2.189065 2.189065 2.189065 ZT8-11 2.5858049999999997 2.5858049999999997 2.5858049999999997 ZT12-15 3.172435 3.0331099999999998 3.31176 ZT16-19 4.162165 4.162165 4.162165 ZT20-23 5.472975 5.472975 5.472975