condition mean min max ZT0-3 4.757996666666666 4.554065 4.98407 ZT4-7 2.697865 2.697865 2.697865 ZT8-11 3.58424 3.58424 3.58424 ZT12-15 4.3080475 4.166905 4.44919 ZT16-19 5.24015 5.24015 5.24015 ZT20-23 6.91902 6.91902 6.91902