condition mean min max ZT0-3 5.993683333333333 4.63907 6.98316 ZT4-7 3.22978 3.22978 3.22978 ZT8-11 1.6368999999999998 1.6368999999999998 1.6368999999999998 ZT12-15 2.0194075 1.859025 2.1797899999999997 ZT16-19 1.59074 1.59074 1.59074 ZT20-23 3.0227000000000004 3.0227000000000004 3.0227000000000004