condition mean min max ZT0-3 1.1799388333333334 0.0522815 2.00686 ZT4-7 0.2576545 0.2576545 0.2576545 ZT8-11 1.721225 1.721225 1.721225 ZT12-15 1.4450005000000001 1.193766 1.6962350000000002 ZT16-19 2.31032 2.31032 2.31032 ZT20-23 2.70869 2.70869 2.70869