Answer: Her income elasticity of demand for cottage cheese is <em><u>0.3333</u></em> making it a <em><u>normal and necessary</u></em> good.
The income elasticity of demand is given by :
The percentage change in income is given as 60%. We calculate the percentage change in quantity demanded as follows:
Substituting the value above in the income elasticity demand formula we get,
<u>YED = 0.33333</u>
Since the income elasticity is positive, and since Shawna buys more cottage cheese after an increase in income, we can classify this good as a normal good.
Since the income elasticity is between 0 and 1 we can also conclude that cottage cheese is also a essential good or a necessity.
