condition mean min max ZT0-3 3.833895 3.833895 3.833895 ZT4-7 2.892245 2.892245 2.892245 ZT8-11 3.916035 3.916035 3.916035 ZT12-15 6.3393049999999995 6.3393049999999995 6.3393049999999995 ZT16-19 5.375735000000001 5.375735000000001 5.375735000000001 ZT20-23 3.880905 3.880905 3.880905