Categorized the Positive income Elasticity

Question

Categorized the Positive income Elasticity?

Answer 1

It can be further categorized in to three

a) Unit income elasticity; Demand changes in same proportion to change in income. It is Ey = 1. 
b) Income elasticity greater than unity: An increase in income brings about a more than proportionate increase in quantity demanded. It is Ey > 1.
c) Income elasticity less than unity:  while income increases quantity demanded is as well raises but less than proportionately. It is Ey < 1.