condition mean min max ZT0-3 4.07654 4.07654 4.07654 ZT4-7 1.87006 1.87006 1.87006 ZT8-11 3.2469200000000003 3.2469200000000003 3.2469200000000003 ZT12-15 5.74766 5.74766 5.74766 ZT16-19 6.2025950000000005 6.2025950000000005 6.2025950000000005 ZT20-23 5.89738 5.89738 5.89738