condition mean min max ZT0-3 3.5172740000000005 3.5172740000000005 3.5172740000000005 ZT4-7 3.2715949999999996 3.2715949999999996 3.2715949999999996 ZT8-11 0.289377 0.289377 0.289377 ZT12-15 3.5033950000000003 3.5033950000000003 3.5033950000000003 ZT16-19 4.630191 4.630191 4.630191 ZT20-23 5.653086666666667 5.653086666666667 5.653086666666667