condition mean min max ZT0-3 2.51308 2.51308 2.51308 ZT4-7 2.090845 2.090845 2.090845 ZT8-11 1.905325 1.905325 1.905325 ZT12-15 1.72578 1.72578 1.72578 ZT16-19 2.691995 2.691995 2.691995 ZT20-23 2.37858 2.37858 2.37858