The Revenue .- It is clear that income affects the amount that individuals purchase most goods and services at any given price. In the case of most goods, the quantity demanded at any price rises with income. Goods that have this property is called normal goods. The so-called inferior goods (such as ground beef that has a lot of fat) is the exception to this general pattern.

TASTES .- Not everyone has the same tastes or everyone remain fixed over time. In Western societies, culture instills like sitting on cushioned furniture while many eastern cities prepares individuals to sit cross-legged on the floor. Therefore the demand for seats tends to be higher in Western countries in the East.

PRICE OF SUBSTITUTE AND COMPLEMENTARY .- The cheese and bread plays a complementary role in the diet of some people. A sharp rise in the price of cheese these people will not only reduce the quantity demanded of cheese but also the demand for bread. In the case of close substitutes such as coffee and tea, a rise in the price of one of them tends to increase demand for the other.

EXPECTATIONS .- The expectations of individuals on furos levels of income and price also affect their purchasing decisions. For example, a person who expects to earn a lot more in the future will likely spend today than to wait for another to earn a lot less. Just as often accelerate our current purchases of goods whose prices expected to rise significantly in the coming months.

POPULATION .- The bigger the market, the greater the amount you purchase a good or service at any given price. For example, in cities with a growing population, housing demand is increasing year by year, while in cities whose populations are declining goes down.

Once we have the supply and demand curves, we can describe the quantity and the equilibrium price of crawfish. Is the pair of price and quantity to which many satisfied buyers and sellers. In other words, is the price and quantity pair that cut the supply and demand curves. The figure represents the balance of our lobster market in which it exchanged a total of 3,000 lobsters at a price of $ 6 each.