condition mean min max ZT0-3 2.2028683333333334 1.59673 2.65165 ZT4-7 1.60043 1.60043 1.60043 ZT8-11 2.041005 2.041005 2.041005 ZT12-15 2.783415 2.5759600000000002 2.99087 ZT16-19 3.08162 3.08162 3.08162 ZT20-23 3.622265 3.622265 3.622265