condition mean min max ZT0-3 3.4833350000000003 3.4833350000000003 3.4833350000000003 ZT4-7 2.298375 2.298375 2.298375 ZT8-11 1.766535 1.766535 1.766535 ZT12-15 3.010755 3.010755 3.010755 ZT16-19 6.92587 6.92587 6.92587 ZT20-23 3.83922 3.83922 3.83922