If a 10 percent increase in income results in an 8 percent increase in the quantity demanded of a good, the income elasticity of demand equals ________ and the good is ________ good. (如果收入增长10%导致需求量增长8%,则需求的收入弹性等于 _ _ _ _ _ _ _ _ _,而且是 _ _ _ _ _ _ _ _好。——中文由在线翻译而来,仅供参考)