condition mean min max ZT0-3 2.6702700000000004 2.44305 2.8974900000000003 ZT4-7 4.153915 4.153915 4.153915 ZT8-11 3.738835 3.738835 3.738835 ZT12-15 0 0 0 ZT16-19 3.963145 3.963145 3.963145 ZT20-23 3.017875 3.017875 3.017875