condition mean min max ZT0-3 3.32642 3.32642 3.32642 ZT4-7 5.874795000000001 5.874795000000001 5.874795000000001 ZT8-11 2.44395 2.44395 2.44395 ZT12-15 1.5802800000000001 1.5802800000000001 1.5802800000000001 ZT16-19 1.9068399999999999 1.9068399999999999 1.9068399999999999 ZT20-23 2.7399050000000003 2.7399050000000003 2.7399050000000003