Chapter 4 was very interesting.  This chapter talked a lot about supply and demand.  Economists use supply and demand to monitor markets and how competitive they are.  There are many buyers and sellers, just like there are many firms and households in the market.  We also learned that quantity of a product is dependent on the price of the good.  For example the higher the price, the less of the product, the cheaper the price, the more of the product.  When the price of a good falls, the amount of that certain good will increase in the market.  Income is also a big determinant in how people will spend their money.  There are also many other factors that effect the demand curve, for example income, price substitute, taste expectations, and the number of buyers.  Unlike the demand curve, the supply curve shapes and slopes upward.  The quantity of a good produced would then depend on the price.  Therefore the demand slope sloes downward, and the supply slope slopes upward.  Other determinants for how much products should be produced include, input prices, technology, expectation, and the number of sellers or people in demand.  The connection of the two graphs will then determine where the market equilibrium is.  Equilibrium is the desired place for supply and demand, to high and there is a surplus of goods, to low and there is a shortage of goods.