宏观经济学原理 曼昆经济学.pptVIP

* Regarding part C: Jane’s purchase causes investment (for her own business) to increase by $1200. However, the computer is sold out of inventory, so inventory investment falls by $1200. The two transactions cancel each other, leaving aggregate investment and GDP unchanged. Regarding part D: This problem illustrates why expenditure always equals output, even when firms don’t sell everything they produce due to lackluster demand. The point here is that unsold output is counted in inventory investment, even when that “investment” was unintentional. * * * This example is similar to that in the text, but using different goods and different numerical values. Suggestion: Ask your students to compute nominal GDP in each year, before revealing the answers. Ask them to compute the rate of increase before revealing the answers. In this example, nominal GDP grows for two reasons: prices are rising, and the economy is producing a larger quantity of goods. Thinking of nominal GDP as total income, the increases in income will overstate the increases in society’s well-being, because part of these increases are due to inflation. We need a way to take out the effects of inflation, to see how much people’s incomes are growing in purchasing power terms. That is the job of real GDP. * This example shows that real GDP in every year is constructed using the prices of the base year, and that the base year doesn’t change. The growth rate of real GDP from one year to the next is the answer to this question: “How much would GDP (and hence everyone’s income) have grown if there had been zero inflation?” Thus, real GDP is corrected for inflation. * The table in the top half of this slide merely summarizes the answers from the previous two slides. This table will be used shortly to compute the growth rates in nominal and real GDP, and to compute the GDP deflator and inflation rates. * Again, the growth rate of real GDP from one year to the next is the answe