(i) When with the rise in income of the consumer demand for the increase, that good is a normal good for that consumer. If with rise in income demand for the good decrease then that good is inferior for that consumer.
(ii) A good is not necessarily inferior for all the consumers. A good which is inferior for a higher income consumer may be a normal good for the lower income consumer. It is not the consumer but the income level of the consumer which determines whether the good is normal or inferior.