condition mean min max ZT0-3 10.443631666666667 7.555115 12.74963 ZT4-7 3.019275 3.019275 3.019275 ZT8-11 2.22487 2.22487 2.22487 ZT12-15 7.6605325 6.38564 8.935425 ZT16-19 4.037475 4.037475 4.037475 ZT20-23 7.07163 7.07163 7.07163