condition mean min max ZT0-3 2.52923 2.52923 2.52923 ZT4-7 2.305695 2.305695 2.305695 ZT8-11 1.964515 1.964515 1.964515 ZT12-15 2.02372 2.02372 2.02372 ZT16-19 4.265420000000001 4.265420000000001 4.265420000000001 ZT20-23 3.225635 3.225635 3.225635