condition mean min max ZT0-3 6.816848333333334 4.600925 8.01512 ZT4-7 3.718345 3.718345 3.718345 ZT8-11 1.676895 1.676895 1.676895 ZT12-15 1.71481 1.613295 1.816325 ZT16-19 2.0967450000000003 2.0967450000000003 2.0967450000000003 ZT20-23 3.501615 3.501615 3.501615