condition mean min max ZT0-3 3.37704 3.37704 3.37704 ZT4-7 2.18765 2.18765 2.18765 ZT8-11 2.897943 2.897943 2.897943 ZT12-15 3.0789400000000002 3.0789400000000002 3.0789400000000002 ZT16-19 2.60863 2.60863 2.60863 ZT20-23 3.48359 3.48359 3.48359