condition mean min max ZT0-3 1.8681125 1.73933 1.996895 ZT4-7 3.55727 3.55727 3.55727 ZT8-11 3.1668950000000002 3.1668950000000002 3.1668950000000002 ZT12-15 0 0 0 ZT16-19 4.3668499999999995 4.3668499999999995 4.3668499999999995 ZT20-23 4.28535 4.28535 4.28535