condition mean min max ZT0-3 5.119688333333333 4.23955 5.652425 ZT4-7 4.98531 4.98531 4.98531 ZT8-11 3.9162850000000002 3.9162850000000002 3.9162850000000002 ZT12-15 10.9659625 10.901274999999998 11.03065 ZT16-19 7.4392949999999995 7.4392949999999995 7.4392949999999995 ZT20-23 5.577735 5.577735 5.577735