condition mean min max ZT0-3 2.1421366666666666 1.916325 2.31001 ZT4-7 3.99716 3.99716 3.99716 ZT8-11 4.312125 4.312125 4.312125 ZT12-15 14.49745 12.3638 16.6311 ZT16-19 7.562155 7.562155 7.562155 ZT20-23 5.97633 5.97633 5.97633