Study Notes for Principles of Economics - Final Exam Suggestion (Mankiw & Arnold)

Measuring a Nation’s Income (Chapter 23)

Definition of Gross Domestic Product (GDP): Gross Domestic Product (GDP) is the market value of all final goods and services produced within a country in a given period of time. It measures both the total income of everyone in the economy and the total expenditure on the economy's output of goods and services.
Components of GDP: GDP (denoted as $Y$ ) is divided into four main components as expressed in the identity:
     $Y = C + I + G + NX$
    * Consumption ( $C$ ): Spending by households on goods and services, with the exception of purchases of new housing.
    * Investment ( $I$ ): Spending on capital equipment, inventories, and structures, including household purchases of new housing.
    * Government Purchases ( $G$ ): Spending on goods and services by local, state, and federal governments. This does not include transfer payments (like Social Security) because they are not made in exchange for currently produced goods or services.
    * Net Exports ( $NX$ ): Spending on domestically produced goods by foreigners (exports) minus spending on foreign goods by domestic residents (imports). It is calculated as: $ext{Net Exports} = ext{Exports} - ext{Imports}$ .
Real vs. Nominal GDP:
* Nominal GDP: The production of goods and services valued at current prices. It reflects both the quantities of goods and services being produced and the prices of those goods and services.
* Real GDP: The production of goods and services valued at constant prices from a designated base year. It measures the total quantity of goods and services produced while keeping prices fixed, thus reflecting only changes in the amount being produced.
Measuring Prices and Quantities (Numerical Problem):
    * Data Table:
        | Year | Price of Hot Dogs | Quantity of Hot Dogs | Price of Hamburgers | Quantity of Hamburgers |
        | :--- | :--- | :--- | :--- | :--- |
        | 2019 | $\$1$ | $100$ | $\$2$ | $50$ |
        | 2020 | $\$2$ | $150$ | $\$3$ | $100$ |
        | 2021 | $\$3$ | $200$ | $\$4$ | $150$ |
    * Base Year: 2019
    * Calculations for Nominal GDP:
        * 2019: $(\$1 imes 100) + (\$2 imes 50) = \$200$
        * 2020: $(\$2 imes 150) + (\$3 imes 100) = 300 + 300 = \$600$
        * 2021: $(\$3 imes 200) + (\$4 imes 150) = 600 + 600 = \$1200$
    * Calculations for Real GDP (Using 2019 Prices):
        * 2019: $(\$1 imes 100) + (\$2 imes 50) = \$200$
        * 2020: $(\$1 imes 150) + (\$2 imes 100) = 150 + 200 = \$350$
        * 2021: $(\$1 imes 200) + (\$2 imes 150) = 200 + 300 = \$500$
    * Calculations for GDP Deflator:
        * Formula: $ext{GDP Deflator} = rac{ ext{Nominal GDP}}{ ext{Real GDP}} imes 100$
        * 2019: $( rac{200}{200}) imes 100 = 100$
        * 2020: $( rac{600}{350}) imes 100 = 171.43$
        * 2021: $( rac{1200}{500}) imes 100 = 240$
    * Calculations for Inflation Rate:
        * Formula: $ext{Inflation Rate Year } Y = rac{ ext{GDP Deflator Year } Y - ext{GDP Deflator Year } Y-1}{ ext{GDP Deflator Year } Y-1} imes 100$
        * 2020: $rac{171.43 - 100}{100} imes 100 = 71.43\%$
        * 2021: $rac{240 - 171.43}{171.43} imes 100 = 40\%$
GDP as a Measure of Economic Well-being: While GDP is a good indicator of the economic health of a nation because it reflects the income available to buy necessities and luxuries, it is not a perfect measure. It excludes the value of leisure, the quality of the environment, and activities that take place outside of markets (such as domestic work performed by family members or volunteer work). It also ignores the distribution of income among citizens.
GDP vs. GNP:
* Gross Domestic Product (GDP): Focuses on the production within the borders of a country, regardless of who owns the factors of production.
* Gross National Product (GNP): Measures the total income earned by a nation’s permanent residents (nationals). It includes income that citizens earn abroad and excludes income that foreigners earn within the country.

Measuring the Cost of Living (Chapter 24)

Definition of Consumer Price Index (CPI): The CPI is a measure of the overall cost of the goods and services bought by a typical consumer. It is used to monitor changes in the cost of living over time.
How CPI is Calculated:
    1. Fix the Basket: Determine which prices are most important to the typical consumer (e.g., specific quantities of certain goods).
    2. Find the Prices: Research the prices of each item in the basket at different points in time.
    3. Compute the Basket's Cost: Calculate the total cost of the fixed basket of goods and services for each year using the prices found.
    4. Choose a Base Year and Compute the Index: Designate one year as the base year. The index is: $ext{CPI} = rac{ ext{Price of basket in current year}}{ ext{Price of basket in base year}} imes 100$ .
    5. Compute the Inflation Rate: Use the CPI to calculate the percentage change in the price index from the preceding period.
CPI Calculation Problem:
    * Basket: 4 hot dogs, 2 hamburgers.
    * Data Table:
        | Year | Price of Hot Dogs | Price of Hamburgers |
        | :--- | :--- | :--- |
        | 2019 | $\$1$ | $\$2$ |
        | 2020 | $\$2$ | $\$3$ |
        | 2021 | $\$3$ | $\$4$ |
    * Cost of Basket:
        * 2019: $(4 imes \$1) + (2 imes \$2) = 4 + 4 = \$8$
        * 2020: $(4 imes \$2) + (2 imes \$3) = 8 + 6 = \$14$
        * 2021: $(4 imes \$3) + (2 imes \$4) = 12 + 8 = \$20$
    * CPI (2019 Base Year):
        * 2019: $(\frac{8}{8}) imes 100 = 100$
        * 2020: $(\frac{14}{8}) imes 100 = 175$
        * 2021: $(\frac{200}{8}) imes 100 = 250$
    * Inflation Rate:
        * 2020: $rac{175 - 100}{100} imes 100 = 75\%$
        * 2021: $rac{250 - 175}{175} imes 100 = 42.86\%$
Nominal and Real Interest Rates:
    * Nominal Interest Rate: The interest rate as usually reported without a correction for the effects of inflation. It tells you how fast the number of dollars in your bank account rises over time.
    * Real Interest Rate: The interest rate corrected for the effects of inflation. It tells you how fast the purchasing power of your bank account rises over time.
    * The Fisher Equation: $ext{Real Interest Rate} = ext{Nominal Interest Rate} - ext{Inflation Rate}$ .

Unemployment (Chapter 28)

Definitions of Labor Categories:
    * Employed: People who work as paid employees, work in their own business, or work as unpaid workers in a family member’s business. This includes those with jobs who were temporarily absent due to vacation, illness, or bad weather.
    * Unemployed: People who are not employed, were available for work, and had tried to find employment during the previous four weeks. It also includes those waiting to be recalled to a job from which they were laid off.
    * Adult Population: The sum of the employed, the unemployed, and those not in the labor force (typically those 16 years and older).
    * Labor Force: The total number of workers, calculated as: $ext{Labor Force} = ext{Number of Employed} + ext{Number of Unemployed}$ .
    * Not in the Labor Force: People who fit neither of the first two categories, such as full-time students, homemakers, and retirees.
Measuring Unemployment:
    * Unemployment Rate: The percentage of the labor force that is unemployed.
         $ext{Unemployment Rate} = rac{ ext{Number of Unemployed}}{ ext{Labor Force}} imes 100$
    * Labor-force Participation Rate: The percentage of the total adult population that is in the labor force.
         $ext{Labor-Force Participation Rate} = rac{ ext{Labor Force}}{ ext{Adult Population}} imes 100$
Types of Unemployment:
    * Frictional Unemployment: Unemployment that results because it takes time for workers to search for the jobs that best suit their tastes and skills. This is often thought to explain relatively short spells of unemployment.
    * Structural Unemployment: Unemployment that results because the number of jobs available in some labor markets is insufficient to provide a job for everyone who wants one. This occurs when wages are set above the equilibrium level (e.g., due to minimum-wage laws, unions, or efficiency wages).
    * Cyclical Unemployment: The deviation of unemployment from its natural rate, associated with business cycle fluctuations.
Case Study: June 2009 Data:
    * Employed: $140,196,000$
    * Unemployed: $14,729,000$
    * Not in labor force: $80,729,000$
    * Adult Population: $140,196,000 + 14,729,000 + 80,729,000 = 235,654,000$
    * Labor Force: $140,196,000 + 14,729,000 = 154,925,000$
    * Labor-Force Participation Rate: $( rac{154,925,000}{235,654,000}) imes 100 = 65.74\%$
    * Unemployment Rate: $( rac{14,729,000}{154,925,000}) imes 100 = 9.51\%$
Demographic Calculation Problem:
    * Total population: $1800$ (Note: Numerical context suggests a hypothetical subset or specific demographic count based on external sheets mentioned in the transcript).
    * Mentally challenged: $2000$
    * Children: $2000$
    * Aged: $3000$
    * Employed: $6000$
    * Note: Using textbook logic, children, the aged, and the mentally challenged are typically excluded from the adult labor force population. Calculating based on provided sheet hints would determine the specific labor force pool from the employed count and remaining unemployed variables not explicitly listed here.

The Monetary System (Chapter 29)

Definition of Money: Money is the set of assets in an economy that people regularly use to buy goods and services from other people.
Three Functions of Money:
    1. Medium of Exchange: An item that buyers give to sellers when they want to purchase goods and services (e.g., currency).
    2. Unit of Account: The yardstick people use to post prices and record debts (the common measure of value).
    3. Store of Value: An item that people can use to transfer purchasing power from the present to the future.
Kinds of Money:
* Commodity Money: Money that takes the form of a commodity with intrinsic value (e.g., gold, cigarettes in prisoner-of-war camps).
* Fiat Money: Money without intrinsic value that is used as money because of government decree. The U.S. dollar is an example of fiat money.
The Banking System and Money Creation:
    * 100 Percent Reserve Banking: A system in which banks hold all deposits as reserves. In this system, banks do not influence the supply of money.
    * Fractional-Reserve Banking: A banking system in which banks hold only a fraction of deposits as reserves.
    * Money Creation: When a bank makes a loan from its reserves, the money supply increases as the borrower now holds currency (a component of the money supply) while the original depositor still holds a demand deposit.
Money Multiplier Scenario:
    * Initial Action: You deposit $\$100$ (previously held under a mattress) into a bank.
    * Reserve Ratio ( $R$ ): $10\%$ or $0.10$ .
    * Total Increase in Deposits: The money multiplier is $1/R = 1/0.10 = 10$ . Therefore, total deposits increase by $10 imes \$100 = \$1000$ .
    * Change in Money Supply: Because the original $\$100$ was already part of the money supply (as currency), the net increase in the money supply is the generated amount through lending: $\$1000 - \$100 = \$900$ .

Aggregate Demand and Aggregate Supply (Chapter 33; Arnold Chapter 8)

Aggregate Demand (AD):
    * Definition: A curve that shows the quantity of goods and services that households, firms, the government, and customers abroad want to buy at each price level.
    * Reasons for Downward Slope:
        1. The Wealth Effect: A lower price level increases the real value of households' money holdings, making them feel wealthier and encouraging them to spend more.
        2. The Interest-Rate Effect: A lower price level reduces the amount of money people want to hold; as they lend the excess out, interest rates fall, stimulating investment spending.
        3. The Exchange-Rate Effect: When a lower price level reduces interest rates, investors seek higher returns abroad, causing the real exchange rate to depreciate, which stimulates net exports.
    * Shifts in AD: The AD curve shifts due to changes in Consumption ( $C$ ), Investment ( $I$ ), Government purchases ( $G$ ), or Net Exports ( $NX$ ) that are not caused by changes in the price level (e.g., tax cuts, investment tax credits, increased government spending).
Aggregate Supply (AS):
    * Definition: A curve showing the quantity of goods and services that firms choose to produce and sell at each price level.
    * Short-Run AS (SRAS) Upward Slope Theories:
        1. Sticky-Wage Theory: Nominal wages are slow to adjust to changing economic conditions; a lower price level makes real wages higher, inducing firms to hire fewer workers and produce less.
        2. Sticky-Price Theory: The prices of some goods and services adjust slowly to changing economic conditions; an unexpected fall in price level leaves some firms with higher-than-desired prices, depressing sales and production.
        3. Misperceptions Theory: Changes in the overall price level can temporarily mislead suppliers about what is happening in the individual markets where they sell their output.
    * Shifts in SRAS: Shifts can be caused by changes in the expected price level or changes in the factors that shift the long-run AS (labor, capital, natural resources, technology).
Long-Run AS (LRAS):
* Vertical Slope: In the long run, the production of goods and services (real GDP) depends on the economy’s supply of labor, capital, and natural resources and on the available technology, not on the overall price level.
* Shifts in LRAS: Shifts occur when there is a change in the quantity of labor (e.g., immigration), physical or human capital, natural resources (e.g., discovery of new minerals), or technological knowledge.
Equilibrium:
* Short Run: Equilibrium is found at the intersection of the AD curve and the SRAS curve.
* Long Run: Equilibrium occurs where the AD curve intersects both the SRAS curve and the LRAS curve at the natural level of output and the corresponding price level.