DEMAND- What affects the level of demand?

price for a product, the quantity demanded for that product will change. If the price of a product falls, the people would have an increase in their real income, which reflects the amount that the real income will buy. Thus with a higher real income, the consumer will buy more of the product. This is called income effect. Likewise, if there is a fall in price for a product, the consumers will be more attracted to this product than those products whose price remained unchanged. Thus, the consumers will buy more of this product substituting for the products bought earlier. Both these will cause a movement along the demand curve in the graph of demand. There are two types of products which affects on how a change in income affects the demand for a product, i.e. normal goods and inferior goods. When there is a rise in the income, the demand for normal goods will increase. as income rises, the demand curve will shift to the right. On the other hand, when there is an increase in income, the demand for products will decrease. This is because the consumers start buying substitute goods of higher price as they can afford it now with an increase in income. Thus this causes the demand curve to shift to the left. The price of products will also affect the demand of a product. Of the goods are substitutes, then an increase in price of one product causes the quantity demanded for that product to decrease and the demand for its substitute to increase.  This causes a movement along the demand curve for the product and a shift of graph to the right for its substitute. If the good are complements, then if the price of product A increase, the quantity demanded for prduct A and the demand for product B, its complement,  This will cause a movement along the demand curve for product A and a shift of the demand curve to the left for product B. Tastes and preferences will also affect the demand of a product. Marketing the goods by advertising the goods will cause the demand curve to shift to the right. The other determinant is the population size as an increase in population will definitely increase the demand for any products. The others are Government policies changes in age structure, changes is income distribution.